Two IDE channels, while redundant for most average users, uses would be multiple HDDs or CD drives (common to have a fast read drive and a slow burning drive). There are also performance benefits, two hard drives on one channel can only access one drive at a time (shared data bus), but two hard drives on separate channels can be accessed simultaneously.
... You know, that explains why my win 95 computer seemed juuuust a bit faster on some games loaded to the secondary HDD after I rearranged things in the case. I put it on the CD's ribbon cable instead of the main hard drive ribbon. Considering the secondary was very slow (it was the old windows drive), I imagine it might have bogged down that newer 7200rpm drive.
Since they were available on higher end 486 boards (or as VESA cards supported in BIOS) I would almost always have them filled with a primary hard disk, secondary smaller one (removable, in a caddy) and then a CDROM. Later on the last channel received a burner. This continued until SATA, at least in my builds. I was grateful to have them.
If you connect two drives on single ribbon, while one wof them is supporting IDE mode and second only PIO4, both of them will work in slower, PIO4, mode.
Another reason why many PCs came with 2 IDE channels is for many years each IDE channel would only run at the maximum speed of the slowest device on a given channel. This was more of an issue shortly ATAPI optical drives became common. Many optical drives only supported UDMA modes 0-2 (16.7-33.3 MBs x-fer rate.) Where later HDDs, especially 7200 RPM ones, supported higher speeds like UDMA 3-5 (44.4-100 MBs x-fer rate.) Later IDE controllers aren't supposed to have this issue but I remember this still happening up until at least the Pentium 3 days. Also, since both devices on a given IDE channel have to share the data bus it made a lot of sense to place a HDD and a CD burner on different IDE channels. Especially in the early days of CD burning when it was very easy to mess up a burn in progress due to a data under-run!
This brings back memories of working on my old Pentium II, with two hard drives and two CD drives (one reader, one burner). It was a horrible, cramped mess and the ribbon cables were never long enough :D
So many years of wondering what it would be like to have more than 1 FDD in one PC. I’ve actually been looking up how it would work, but this video is SO MUCH MORE SATISFYING!!! Especially seeing all those drives built into a truly legendary case! Shelby, thank you so much for this awesome video. It answers a lot of questions for a lot of people, I’m sure!
If you enable the external third or fourth floppy drive on the IBM PC/XT, the hard drive will be moved to D: or E:, respectively. I discovered this when adding a hard drive to my dad's IBM Portable PC, and was surprised to see it show up as E:, because for some reason its motherboard left the factory with the DIP switches set to indicate it had four floppy drives. Also some early pre-XT hard drive controllers which required a boot disk would assign the hard drive to A: after loading the driver software and move the first floppy drive to B:. This is also the way the TRS-80 works -- if you add a hard drive, it shows up as drive 0, and the floppy drives move up to become drives 1, 2, 3, etc.
@@初生之鸟 I can confirm. On my 5155 my hard drive was drive D: until I upgraded to DOS 5. It was actually a welcome change because having your hard drive as D: broke a lot of install batch files and other stuff.
@@初生之鸟 But what about DOS-less computers, such as those running Windows XP or later? I have had various Dual-Boot scenarios with either 2x XP, XP + Win7, or Win7 + Win7, and in all cases the currently active O/S will always assign the letter C: to the partition it booted from, while the "dormant" one will be D: and when i boot from the other O/S, its partition then becomes C: and vice versa.
@@BertGrink In NT-based Windows the drive letter assignments are stored in the registry. Pre-Vista it's super easy to have Windows accidentally on a non-C letter. I'm sure I've run across Windows installed on D:\WINNT before. You must have either done something special or have been really lucky to get each installation to see its own drive as C:.
@@eDoc2020 No, I haven't done anything special, and I would rather have the partition letters be the same regardless of which one i boot from; i.e. 1st partition should always be C:, 2nd always D: and so on.
The Shugart 8" drives had four drive select wires. A jumper on the drive selected between "radial" drive select and "linear" drive select. The Linear select used one wire per drive for a max of 4 drives. The radial select used one wire to enable the drive, and the other three wires were BCD encoded. In this mode you could have a max of EIGHT drives on the cable! IIRC the 5.25" drives were similar, but could only handle a max of 4 drives (radial) or 3 (linear).
I remember years ago someone on a retro computer discord had a fun 360k floppy that had been half-overwritten in a 1.2mb drive. On one of his computers it would read the original data, and a different would read the new data.
A few years back when I built my first modern computer instead of always having really old Frankenstein systems from my uncle he asked me about all the disc and disk drives and was shocked at how easy they were to set up. Lol I knew there were hoops to jump through for multiple drives but I didn’t know it was that annoying. Now I know why he was so shocked.
I've only been following the channel since the trip to Canada. Even just since then, the camera quality has gone up. The editing and cuts to B roll feel smoother and more frequent,.which is more engaging, and even the scripting has really stepped up. This is just blowing my mind when it comes to quality and content. Great video, super cool and informative. You sir, are crushing it.
This finally explained to me one of the questions I've had for about 30 years now: why my very old XT hardware documentation about floppy drives seemed to be incorrect. Thank you so much for not letting me die unknowing!
I REALLY need/want to get my Win98 machine to have 3 floppy drives for getting data to and from all my machines. Another awesome video, very well researched and I learned stuff. Only thing I'd tweak is the 4 drive IDE thing, that only became a standard thing sometime around the intro of the Pentium architecture, and it was not done for Hard Drive support, more for optical drives and other non-hard drive devices. When CD-ROM drives shifted from SCSI to IDE people starting realizing that a single IDE channel was not enough, and then later on when drives increased in speed it became apparent that having slower IDE drives on the same channel as the high speed HDD was degrading performance, so the demand became to add a second IDE channel on boards. So the evolution to 4 IDE drive support had not much to do with having 4 HDDs, more to do with performance and the desire to have multiple other IDE devices.
Especially that in a typical machine with one hard drive and one optical. If you were to upgrade the storage (let's say you bought a fancy new, 2 GB drive) with a single, 2-port controller, you'd have to either image over your installation or make a new one. And there would be no way to do that move while booting from CD, because that is where the 2nd hard drive sits. Basically, out with the old drive in with the new, boot from CD, install the new system, CD drive out, old hard drive back in, move your stuff over, old drive out again and CD back in again. But with 4 ports, you could just hang the new drive behind the old one.
The twist in the cable was introduced with the PC/AT and then carried over to the XT during its time of production overlap with the AT. Texas Instruments also used normal Shugart interface floppy drives with their controller for the 99-4 and 4/A using a straight through cable with all female connectors and special male/male connector PCBs to swap the ID lines for the two external drives while the single internal drive used a 34 pin 0.1" header to card edge cable. It's also possible to custom wire a cable and skip the little connector PCBs. Unfortunately TI neglected to make their floppy controller with double density support, leaving that up to the aftermarket. But there is a way to modify the TI controller to use 80 track 720K (3.5" or 5.25") drives as 360K single density. Most of the aftermarket controllers also supported 4 drives.
3:56 Apple didn’t need an interface *board* for its floppy drives: it had an interface *chip* . This was because it didn’t bother with actual hardware to do the encoding and decoding of the magnetic signals: this was all done in software, courtesy of that hardware genius, Mr Steve Wozniak.
In the 1990s, I decided to try and use an 8" drive on my PC, while keeping both 5.25" and 3.5" drives. My first 4-floppy FDC has been a controller made by GSI, with 2 x 34-pin connectors on the board. My setup was then A: 1.2M, B: 1.44M, and the 8" got the letter D: and was set as 1.2M in the BIOS. An 8" is really a big 1.2M drive, but with 77 tracks instead of 80. I could format blank 8" disks with DOS, and the stepper would knock 3 times at the end after track 77. No error message on FORMAT, that's normal, but I know I couldn't use the 3 last "non existing" tracks. Still cool by 1994 to write data and hear the loud stepper of the 8" drive. They were well gone by then! The challenge was to make the home made adapter from th 8" 50-pin bus to the standard PC 34-pin floppy. The 8" drives were in an external casing with its own 24V power supply, which is different and bigger than the standard PC 4-pin Molex. I still have all my equipment today, plus I bought the MicroSolutions CompatiCard IV in the early 2000s. This is the holy grail of disk controllers, and it also supports 4 floppies. It came with their special 50-pin to 34-pin floppy cable adapter, so I didn't need to use my home-made anymore, that was quite fragile (it was a piece of art, connecting thin wires between the 50-pin female and the 34-pin female, and if one got too loose, I lost a signal and got an error). I was glad to get the PCB adapter with 50pin and 34pin connectors from them... The CompatiCard IV is able to read/write FM Single Density, in particular the IBM 3740 format developped in the 1970s, which is 8", 77 tracks, 26 sect/track, and 128 bytes/sect. Although this predates the IBM PC, I was still able to read the data sector-by-sector, and take disk images, using the program ANADISK. The file size is 256,256 bytes, so 250.25 KB... I also got 86-DOS on that format, as well as early non-PC CP/M-86 versions from 1980-81...
They were a pain in the bum. Only certain types of floppy interface ran fast enough for them, and even then only on a good day when the wind was blowing in the right direction.
@@Alexis_du_60 Yeah! That's what they were called, for the life of me I couldn't remember... Even though I had one that I inherited from my mom's office way back.
@@orionfl79 I never had luck trying to find one, and the few I found had some weird gooey and sticky stuff oozing out of it... Probably the rubber rollers breaking down? I don't know for sure.
Funny you mention the PS/2, as the models 25/30/40 were indeed limited to 2 floppy drives, but models above that were not, eventho that did require adding controller cards. For years I've had a PS/2 model 80 around which had 2 internal drives (2x 3.5" 1.44mb) and 2 external drives (5.25" 360kb and 5.25" 1.2mb). That was an officially supported configuration (I worked at IBM at the time and did support for PS/2 machines). This machine was used for archiving media, it also had an internal worm drive for storing archived disks. However, support for those extra drives was provided by the option roms (and related settings), not directly by the bios.
Superb video as always! I tried doing the exact same setup as you but I used a BIOSless card. I did manage to get one of those DOS config.sys drivers working ... But really compatibility sucked and while the drive worked in DOS, disk imaging software had issues with the third drive. (1.2mb in my machine as well ) Even with your setup I'd imagine software like IMD still can only see A and B....
In this case I was using DSKImage, I've not made friends with IMD yet. Every time I try it it seems like I always have to convert images three different times to a format it will accept. DSKImage just has you write out a string describing the drive as ID:Sides:tracks:sectors and it will send raw commands to the drive with that. So I set it to ID 2 with the rest of the values for a 1.2MB drive and it worked perfectly for me. I wouldn't be surprised if there is software that is hardcoded with 2 drives only or some other oversight though The problem with a second controller is, for the most part I believe, that the TSRs for them attempt to remap the 2nd controllers drives 0 & 1 to the address of the 1st controllers drives 2 & 3. So if you use something that somehow by passes the TSR then it doesn't work. But I never even got the second controllers drives to show up in DOS, so there there's some speculation there.
@@TechTangents ah yes I've used DSKimage and that would definitely work. I end up with IMD because of its support of FM disk formats and also mixed FM and MFM in one disk which the TRS80 M1 uses. But of course no vintage machine uses a 1.2mb drive so who cares really! LOL. The detail in your video was so spot on -- the best explanation I've ever seen in one place so it'll be a resource for the future if anyone else tries to do 4 drives.
I remember how unlucky I was that the FDC interface required buying the overpriced expansion box, thus limiting me to 2 standard cassette recorders and the 4K RAM in the Mini Memory module.
@@johndododoe1411 Not true! The P-Box came late, as users started having too many sidecars. There was a sidecar disk controller from TI, as well as several third-party controllers.
I've always wanted 4 floppy drive support for the same reason you did. I have never found a 4 drive controller in the wild, though, so you lucked out there. I didn't know about the XT FDC either. I will look into that. I remember watching a video on UA-cam (but can't remember from who) where they had a motherboard with 4 floppy support in the BIOS, and he needed to use 2 floppy controller cars with configurable IRQ and DMA to get it to work. I think it was some 386 board, but I could be mistaken. I imagine that's even rarer than finding a 4 drive controller. The one thing that would be really neat is if something allowed this and also enabled 3 mode support on the 3.5 drive, for reading that odd format on Japanese PCs that used 3.5 inch drives, but ran them as 5.25 1.2 MB drives.
Ahh, the IBM PC AT It was the bees knees at the time. Mine had two HD floppies and two 40MB HDDs. I had reasons ... Mostly, I was a developer and having the source file on one HDD and the output on the other almost doubled the speed. Two floppies were for making copies. Again, speed was the incentive. In the case of the floppies, it made copying much more that twice as fast. I should get a PC, and XT and an AT ... and possibly a 386SX (I had good memories of one). I'm sick, aren't I? Especially considering I have a bout 30 8-bit systems and a PDP-11/74 cluttering up my 'show room'. How about a Micro-VAX????
Hey hey you're finally talking about something I knew before hand! Still gonna watch it anyways because I love the production quality! One of my many Taiwanese clone PCs, based on the DTK Turbo 640 board, left the factory with two floppy controllers and 3 drives! One controller was configured in slave mode, which is an interesting thing to set up. The second controller was controlling the third drive, which because of the ancient hackjob of a BIOS and the old version of DOS I have to use to make that work at all, and the lack of a fixed disk controller (which crashes the garbage BIOS), the floppy drives are A, B, and C. Funny enough, I've got some weirdo Asian import no-name motherboards going all the way up to the early 2000s (AMD Socket 462) which list a "Third floppy support" in the BIOS and will let you connect a third drive on a different drive select on the same cable. I've never come across the actual cable, but jamming some wires in a breadboard I did actually manage to see it work, at least enough for Windows to show a disk drive in "F:" (That particular computer has two optical drives). Since most controllers internally support four drives, and since you can get BIOS extensions to make those extra two drives work, you should in theory be able to modify a standard diskette drive controller, or even an onboard one to allow four drives. Most off the shelf drive controllers you see in IBMs are pretty well documented Fairchild or Zilog parts or whatever, stuff you can find datasheets on without too much hair pulling EDIT: Haha, you talked about it in the video. The only BIOS I've seen that supports a second controller is that absolute garbage Taiwanese clone BIOS, which doesn't even do a proper memory test. No EGA support either, MDA or CGA *only*. It's probably the least functional it could be to make the machine work, but it does have that one random advantage that it happens to work with a second address card. Supposedly it supports the same for video cards and hard disk controllers, but adding a second video card causes the machine to act very strangely (switches between the cards at random, think displaying half a word on one card and the other half on the other), and adding a hard disk controller period will cause it to hang on boot Finding the jumper settings isn't terrible for most cards! Have you tried Total Hardware 99? Statson.org is a reupload with a more "modern" layout and lots of ads if you're more comfortable there. th99.infania.net is where I go to get all mine. Is your LS-120 drive really that unreliable? I've never had a problem with any of the three I have laying around, as long as you keep the heads clean and the rails lubed like any other drive it'll be just as reliable. The lack of direct hardware access might cause you drama, though. I have a lot more issues with iomega drives (ZIP, JAZ, ditto, Clik!, etc) failing and eating media. I'm interested in the "CA9277B-21" card you mentioned in the video, would you be open to dumping and posting the BIOS extension on that card?
Wow wow wow!! Thanks for this video :) Gotta admit, i like retro stuff in general, but floppies have a special place in my heart. My first computer was a ZX Spectrum clone, and I was so jealous at the time of the more modern machines that had floppies since it was so much faster than tape :) Then i got an 8086 and started hoarding a number of floppies, some of which i lost last couple of times i moved, but i still have a great deal around. Setting up one of my old machines to have 3 floppies + my IDE zip drive was an idea I had bouncing in my head for quite a while now. Maybe i can learn something from your videos. Anyway, sorry for the rant. Love your content! Cheers!
I had an after-market floppy disk controller for my ZX Spectrum - I think it might have been the MGT DISCiPle one iirc - not sure - it was over 30 years ago :) but I had that connected to a 3.5" 360K single sided floppy drive. It was an amazing step forward from loading games off cassette tape, that's for sure :) and it also has a so-called "magic button" that you could press after you'd loaded a game off tape and that would dump a full memory snapshot of the RAM to disk, which is how I put games onto floppy. Since I had a 48K Spectrum at the time, I was able to get 7 games on a single disk, which was pretty damned impressive at the time (around 1988-ish)
Incredibly informative video. I love deep dives like this. I wonder how 5.25 disk duplication worked on a large scale back in the day - though conceivably those machines wouldn't actually "read" or have a drive letter they would just write...
Those kinds of cards with extra controllers but no BIOS are probably useful for like mass disk copy operations where you write some custom software to address the ports directly.
I like the video because it's hard to keep up with everything. The XT-FDC and Sergey's FDC is going to be worth checking out. The twist in the ribbons motor control is not an IBM thought, it's actually from hacks that were used to help techs swap out floppy drives and reduced the time to switch. The manufacturers picked up on it and adopted it as standard practice. The two common reasons we needed several floppies were 1) copying floppies over several drives at the same time reduced the time it took to copy floppy to floppy. If a person looks way back in the old catalogs they could find "towers" much the same way people can find cd towers. 2) more commonly, it was easier to load software by redirecting a drive already loaded with the next disk rather than simply flipping floppies. Most floppy controller boards had at least IRQ jumpers that the controller can be assigned, the real problem was figuring out which IRQ was free. While the on board bios supported A and B drives, it was largely because the controller was on the board, and it was common that the default system files were on the A drive, the B drive was included since the controller supported two drives. More floppy drives got an extended letter after the hard drive mainly because the bios support for four hard drives (in most cases) meant they had priority over the next available drives that is not in the bios. C,D,E,F were often reserved for hard drives unless there was one HD controller on the board then C,D. After that then the installer had to manually assign the drives either by pin or in the config,sys working with the software driver. The reason Manufacturers reduced the inclusion of floppy drives over the years was that by the time CD's started being used for software storage, the writing was on the wall for floppies.
BIOS doesn't assign or use drive letters, they simply referred to floppy drives number 0, 1, and higher, plus hard drives 128, 129 and higher . BIOS user interfaces were added later and used the DOS letters for familiarity . I'm unsure hoe the new BIOS interfaces like ABIOS and EFI index drives .
I like the outro of showing the machine working on its own. It reminds me of the end credits for episodes of _Are You Being Served?_ when they would show product displays from earlier going haywire..... except, we don't want to see PCs actually going bad, unless it's a gag setup, like a smoke machine with lighting tricks.
Dude I'm having a heck of a time getting one 5.25 floppy working in winxp. The bios supports and is selected to 5.25. The drive powers and spins but doesn't seek. Idk man maybe the drive is broken. Anyways awesome video you've helped thousands of people.
I think that's the first time I've seen someone populate all 6 bays in a tower. I do seem to vaguely remember the 4 drive set up for TRS PC's, but never had experience as my only TRS machine was a CoCo2 and even a single floppy was out of my price range. I think if I ever got into what they now seem to call "retro computing", I'd be one of those guys who would only use old media for kicks and for day to day fun I would use those kits I've been seeing that allow modern flash hardware to mimic floppies. Even back in the day, one of my goofy side projects was to put win 3.1 on a CD to see how fast I could install it. It seemed stupidly fast to me at the time, lol.
Many controllers supported up to 4 floppy drives. The big PC companies didn't often support more than 2. But many of the generic clones that were made from a collection of parts did offer up to 4.
Some machines used 80 track DSDD 5¼" formats with BIOS routines mapping sector sizes like modern hard discs do. This pushed capacity way above the PC limitations .
Adding a second (or third or fourth) floppy controller works perfectly with Linux as long as you supply the io-Adress and IRQ on the kernel command line or the module command line - disclaimer, I am talking about kernel 1.0 or 1.2, not sure if this still works today. In fact I once took an "non-configurable" floppy controller and rewired the ISA connectors adress lines so the IO landed in a VERY strange place. Worked like a charm in Linux as fd2 and fd3 - I might had to mknod the devics manually under /dev/ but thats trivial. I am not sure if the minor nodes where like 0,1,2,3 or 0,1,64,65 but I think the later was true and it was visible from the kernel boot log. In hindsight FreeDOS could support that too as I remember it has an option for additional IO-ports for floppies. Maybe a seperate DOS driver could do the same but then I am not aware of anything like that.
note the floppy controller from the 70's ran from 40 pin scsi device, the late 80's to early 90's floppies seen from windows 3.1-win 8 .. with the major shift to pci-e you have major issues in connecting up older hardware unless someone creates a sata line type floppy interface
I fucking love Nextcloud. Been using it for several years, hosted on my own server. It's been immeasurably useful over the years beyond it's usual cloud backup services
I never knew that you could get 4 floppy drive support or the cards to make it happen. Good bit of info that pal! i always thought IDE and SCSI were the ones to have for extra drives.
The additional MR BIOS (Microid Research) has support for 4 floppy drives natively with two 2 floppy drive controllers. It replaces the original bios on the motherboard
IMO leaving the unneeded (for almost all people) 4 drive support is similar to the use of 2 digits for year representation. It doesn't require extra info/worry/etc. when its not needed in most cases (over than when you switch centuries... or are doing copying between formats in your example).
+1 for making a FluxEngine at some point. I basically only ever used 'boring' 1.44Mb IBM PC floppies in my time, but still I built one to backup my collection just because it was a cheap and easy weekend project, and modern USB floppy drives are just garbage. You actually come across more exotic discs, so you have even more reason to have one around (even if you do have the proper hardware to read them).
You should add a 720K 3.5 inch drive, because although you can read 720K disks from a 1.44 drive, writing disks does NOT work reliably (supposedly due to magnetic strength or something)
It's the other way around - writing to a 720k disk from a 1440k drive is reliable, but not 720k drive to 1440k disk. The magnetic impedance of a DD disk is lower than an HD disk, so you actually need less of a magnetic field to permanently flip the bit. The drive head of an HD drive has a higher magnetic field strength.
a few years ago I found an old PC almost like this with 4 drives in it (I forget the configuration, but it was a huge tower PC from the early to mid 90s I was guessing). It was $50, I wish I got it cause it was pretty awesome.
Conversely, as more and more motherboards drop support for floppy drives entirely, it's possible to assign the drive letters A: and B: to one or two hard drives / SSDs / USB drives et.c. Very interesting video by the way; I was aware that many FDCs had support for up to 4 drives, for example the uPD765 which is a very common IC - but again with the caveat that it can only support one /Motor-On signal. Whether the floppy drives themselves can decode the 2 Select lines to 4 individual IDs is another matter altogether, though.
It is possible to install more than the standard two (IDE) floppies, in that you use SCSI FDD, internally or externally, connected to one or more SCSI host adapter.
Good old I/O cards. Back then I got one from a friend and plugged into my Pentium MMX, so that there was another IDE channel, floppy channel, serial ports etc. I can't exactly remember (20 years back) what happened / whether it worked or not though. I think now we can just use 4 USB floppy drivers easily.
I'd like to know how we used to install a master and slave HDD in... say, a 486, or a Pentium. When my HDD was dying, a friend gave me a second HDD, but I couldn't get them both working on the same machine at the same time. Thus, anything I wanted to save from the dying drive, had to be copied by 3.5" floppy as it was my only other option. I did get most everything transferred, but not everything due to the size limit of the floppy.
I did some digging into the logo and and the model number on Shelby's card. I found a 5 year old forum post that mentioned the company called "Relialogic Corporation PTE Ltd." out of Singapore. I'd take it with a grain of salt, but it's all I could find after searching for well over an hour. I did uncover other cards that are suspected to be from the same manufacturer.
Indeed, with a dedicated 4 drive controller with its own BIOS extension, making a 4 floppy drive system isn't that hard. I have made such a system myself. Demo video is also on YT. Using 2 separate controllers with the secondary at port 370h is the real challenge though. It can be done if IRQs and DRQs are different between the 2 controllers. Then there is either BIOS support or an OS driver needed to access drives 3 and 4. Being unable to find a DOS or Windows driver for this, I used the BIOS extention from Sergey's FDC to realize this. This works, although it isn't very fast and stability in Windows 95 is an issue. However, unlike with a 4 drive controller, having 2 separate controllers allows one to read or write 2 different floppies in parallel in the same system --> try to achieve that with a standard 2 drive system; the first drive pauses the moment the second drive is accessed.
And on another note, the 1.2mb drive versus 360kb drive... that is a problem when overwriting a floppy formatted on a 360kb drive with a 1.2mb drive. The result of that would not be properly readable. But in itself, a 1.2mb drive can read both 360kb and 1.2mb 5.25" floppies without problems.
On my 1983 HP 150 Touchscreen the 3.5" floppy drive is B: and the 15mb hard drive is A: (unless you have it boot from floppy then the other way round). The joys of early DOS compatible but not PC compatible computing! It runs custom DOS 2.11 BTW and the floppy is not 720k but a 710k custom format so some special dos drivers need to read/write to them.
I'm going to have to look into my old 286 at my parents' place because it has 4 floppy drives in it! 2x 5.25" and 2x 3.5", each size format with a DD and HD drive! I never looked into why or how all drives were supported at the time!
That logo on your card was for a company called patriot. They closed shop forever ago she a new company is using there name. I have a few old cards made by them.
Wow, what a flashback. On the old atari ST you could use pc drives in it. Including the external boxes. And yeah you could mess things up if a drive was set at ID 3 or 4. The teac 3.5 drive 0 & drive 1 pins were binary, so it was actually a binary 0-3. For backwards compatibility. I really screwed with some friends back in the day by setting drives to 2 or 3 aka drives 3 & 4.
I have never gotten the chance to obtain such a big full-sized ATX case, especially one made of steel. Gloriously heavy indeed, and allot of space to put a smaller motherboard inside (or two!) and two power supplies (hard disk cavity was massive enough!), along with six (6) cooling/exhaust fans. Yeah, that's still my damn dream. xD Current machine runs GNU/Linux (mint), windows 10 on a secondary drive (fucking never use it lol), has 24GB RAM (DDR3) and quad core AMD Athlon(tm) II X4 620 Processor at 2.6 GHz along with AMD HD series graphics.
Nice video, also wanted to mention i actually tried to sign up for linode using your code but my account was immediately banned i tried contacting support and they refuse to share any information as to why they did that, i checked all my information and they basically refuse to help in any way. So yea quite an unfortunate experience.
Just FYI - The the hard drive is "C" is MS DOS doing it on purpose. That behaviour didn't start until MS DOS 5.0. Earlier versions would've mounted the floppies as ABC, then done the hard drive partitions starting at D. It's not actually related to what was detected when. Great video, and loved seeing that IO card. I need to find one myself!
How do tape drives like the QIC 80 fit into all this? They were usually directly connected to the floppy controller with a special cable which in turn had a connector to which the floppy drives were connected. Would this mean the QIC 80 drive would actually be adressed as the 3rd or 4th floppy drive?
I still have my TRS-80 MOd I with 4x floppy drives. I dare not plug it in lest it burst into flames -- I'm sure the components are unstable, especially the caps. It hasn't been powered on since the late 80s. I just can't bear to get rid of it.
Nice video ! I have XT clone and as usual it support 4 Flippyes configured with jumpers on the motherboard. The question is how to configure it for no Flippyes at all, it have to be 1, 2, 3 or 4 , but not have option for 0 . It is annoying to press F1 every time on the POST, beciuse I have no floppy controller and floppy drives in the system
I had an Amiga that could take four floppy drives(drive 0 was internal to the computer, drive 1 was an external which had another external connector for daisy chaining in drives 2 and 3), and even before I got the hard drive, there was never an occasion where I'd need more than 2 drives, other than installing a new program. The cost wasn't worth the use case.
Yep, my Amigas and C64s would have more than 2 floppy drives connected on multiple occasions. Why might someone routinely need more than 2 floppy drives? er.. um.. yo ho yo ho... ;-)
@Mr Guru I have a nice little device in my A1200 which allows me to use up to 4 IDE drives at once; one port has a standard 40-pin connector, and the other has both a 40-pin and a 44-pin 2½" connector, but only one of those can be used at a time.
Alright, since you're quite knowledgeable here, you might be able to help me out. I'm looking to make a PC like the one you've got (entire front panel filled up with stuff, maybe even six big bays and two small ones) that'll allow me to read different and sometimes exotic types of storage media, but also be reasonably useable for today's applications. That's why I've been thinking of a core 2 duo era motherboard. The problem is that they a) don't have ISA slots so I won't be able to use an old ISA floppy controller with them and b) even if they have built-in FDD, due to the period those can usually handle only a single FDD drive. In addition to having both a 1,44 MB 3,5'' and 1,2 MB 5,25'' drive, I want that PC to have a dvd-rw, a 750MB Zip drive, a 2,3GB magneto-optical 3,5'' drive (50 pin SCSI) and a multi-card reader, in addition to free USB support for moving data to newer devices. IDE and SCSI are easy - there are PCI controller cards for those, so I'm not worried about them. I also know I could just hook the 5,25'' drive into the FDD slot and convert the 3,5'' drive into USB via an adapter and plug it into one of the motherboard's USB pinout. The 3,5'' drive will detect just fine that way. There are also those "combo drives", like the ones Teac and Epson made, that combine 3,5'' and 5,25'' drives in a single 5,25'' form factor - and they use all the same connectors as 3,5'' drives. If I could get my hands on one of those, I could probably make it work with a mobo that only supports a single FDD drive. The question though is - would they be recognized by the system as both A and B, or just A, meaning it couldn't have two diskettes inserted simultaneously?
i assume mainboards often came with 2 ide ports because the single controller supported 4 drives much mike modern high end Z490 boards still have a ps2 port
Probably. But did you know Windows can be installed on any drive letter (at least before Vista)? The NT based ones can even boot with absolutely no C drive. I've had this accidentally happen when installing 2000 or XP when there's already a formatted drive in the system.
@@eDoc2020 i took a class on OS troubleshooting that involved managing five separate installations of NT on the same hard drive. it was quite the nightmare. parts of Windows and some Windows software expects Windows to be installed on C:, and will behave very strangely if that's not the case.
@@iceowl Even with properly behaved applications the different Windows installations will use the same 'Program Files' directory and you'll get lots of mismatches. Now whenever I need different Windows versions on the same drive I'll use a different partition and either hide the other partitions if I'm booting the installer from CD or delete/modify the migrate.inf if I started the install from within a different Windows installation.
Man they are so difficult to find, those 4 drive controllers. Really hoping there's enough of a push for these that someone comes up with a new solution.
The use of a progress bar for the ad/sponsor is a nice touch.
@The Lavian This video is sponsored by.. right arrow x6.. and again if needed
@The Lavian I installed... wow haha,, tho I was always pretty good at skipping ads, either with the seek bar and now with the right arrow x6 :D
yeah it is imo
Tech Tangents and Adrian's Digital Basement on the same day! nice!
same thought. what a great day!
I thoroughly enjoy both channels as well!
Adrian uploaded? I didn't get that notification. UA-cam at it again.
Shivambu that whole notifcation system is broken
@@schutz85 As a heads up, it seems like he uploads twice a week, Saturday, and usually wednesday for a mid-week mailcall
Two IDE channels, while redundant for most average users, uses would be multiple HDDs or CD drives (common to have a fast read drive and a slow burning drive).
There are also performance benefits, two hard drives on one channel can only access one drive at a time (shared data bus), but two hard drives on separate channels can be accessed simultaneously.
... You know, that explains why my win 95 computer seemed juuuust a bit faster on some games loaded to the secondary HDD after I rearranged things in the case. I put it on the CD's ribbon cable instead of the main hard drive ribbon.
Considering the secondary was very slow (it was the old windows drive), I imagine it might have bogged down that newer 7200rpm drive.
Since they were available on higher end 486 boards (or as VESA cards supported in BIOS) I would almost always have them filled with a primary hard disk, secondary smaller one (removable, in a caddy) and then a CDROM. Later on the last channel received a burner. This continued until SATA, at least in my builds. I was grateful to have them.
If you connect two drives on single ribbon, while one wof them is supporting IDE mode and second only PIO4, both of them will work in slower, PIO4, mode.
@@Vein1986 Yep, always will follow the lowest common mode.
Caused many headaches back in the day when UDMA modes came out. lol
It was also important to have two CD drives to copy a friend's CD! Who had half a gig on their hard disk just lying around unused for disk caching?
The whole time i'm watching i'm thinking that table is gonna collapse
Once again a lovely video and i love this oddball stuff.
Yea, I was afraid a Linus would happen.
I thought the big-ass tower would collapse.
Another reason why many PCs came with 2 IDE channels is for many years each IDE channel would only run at the maximum speed of the slowest device on a given channel. This was more of an issue shortly ATAPI optical drives became common. Many optical drives only supported UDMA modes 0-2 (16.7-33.3 MBs x-fer rate.) Where later HDDs, especially 7200 RPM ones, supported higher speeds like UDMA 3-5 (44.4-100 MBs x-fer rate.) Later IDE controllers aren't supposed to have this issue but I remember this still happening up until at least the Pentium 3 days.
Also, since both devices on a given IDE channel have to share the data bus it made a lot of sense to place a HDD and a CD burner on different IDE channels. Especially in the early days of CD burning when it was very easy to mess up a burn in progress due to a data under-run!
You should fix that table, so shaky :)
ua-cam.com/video/frwLir1A_qg/v-deo.html
This brings back memories of working on my old Pentium II, with two hard drives and two CD drives (one reader, one burner). It was a horrible, cramped mess and the ribbon cables were never long enough :D
So many years of wondering what it would be like to have more than 1 FDD in one PC. I’ve actually been looking up how it would work, but this video is SO MUCH MORE SATISFYING!!! Especially seeing all those drives built into a truly legendary case!
Shelby, thank you so much for this awesome video. It answers a lot of questions for a lot of people, I’m sure!
If you enable the external third or fourth floppy drive on the IBM PC/XT, the hard drive will be moved to D: or E:, respectively. I discovered this when adding a hard drive to my dad's IBM Portable PC, and was surprised to see it show up as E:, because for some reason its motherboard left the factory with the DIP switches set to indicate it had four floppy drives.
Also some early pre-XT hard drive controllers which required a boot disk would assign the hard drive to A: after loading the driver software and move the first floppy drive to B:. This is also the way the TRS-80 works -- if you add a hard drive, it shows up as drive 0, and the floppy drives move up to become drives 1, 2, 3, etc.
The first harddrive is fixed to C starting from DOS 5. But in 3.3, you can get a floppy on C or D.
@@初生之鸟 I can confirm. On my 5155 my hard drive was drive D: until I upgraded to DOS 5. It was actually a welcome change because having your hard drive as D: broke a lot of install batch files and other stuff.
@@初生之鸟 But what about DOS-less computers, such as those running Windows XP or later? I have had various Dual-Boot scenarios with either 2x XP, XP + Win7, or Win7 + Win7, and in all cases the currently active O/S will always assign the letter C: to the partition it booted from, while the "dormant" one will be D: and when i boot from the other O/S, its partition then becomes C: and vice versa.
@@BertGrink In NT-based Windows the drive letter assignments are stored in the registry. Pre-Vista it's super easy to have Windows accidentally on a non-C letter. I'm sure I've run across Windows installed on D:\WINNT before. You must have either done something special or have been really lucky to get each installation to see its own drive as C:.
@@eDoc2020 No, I haven't done anything special, and I would rather have the partition letters be the same regardless of which one i boot from; i.e. 1st partition should always be C:, 2nd always D: and so on.
The Shugart 8" drives had four drive select wires. A jumper on the drive selected between "radial" drive select and "linear" drive select. The Linear select used one wire per drive for a max of 4 drives. The radial select used one wire to enable the drive, and the other three wires were BCD encoded. In this mode you could have a max of EIGHT drives on the cable! IIRC the 5.25" drives were similar, but could only handle a max of 4 drives (radial) or 3 (linear).
In some bizarre universe, LinusTechTips is now making a video on installing 8 floppy drives in a single computer.
Plot twist: LTT will make a video on this
RAID0 on 16 FLOPPY DRIVES ON ONE PC?
Actually, that sounds very interesting to watch 🤔
I hope not, I don't want him ruining the old section of my hobby too
@@AiOinc1 What do you mean ruin?
@@lgibson02 Sometimes when someone popular makes a video on old tech people buy up a lot of what's on the market and what's left is price scalpers.
I remember years ago someone on a retro computer discord had a fun 360k floppy that had been half-overwritten in a 1.2mb drive. On one of his computers it would read the original data, and a different would read the new data.
That's quite interesting; if it was reliable enough you could double the amount of information you can store on a single floppy.
A few years back when I built my first modern computer instead of always having really old Frankenstein systems from my uncle he asked me about all the disc and disk drives and was shocked at how easy they were to set up. Lol I knew there were hoops to jump through for multiple drives but I didn’t know it was that annoying. Now I know why he was so shocked.
How modern was that?
Fascinating video, took me back to my old days cutting my teeth on DOS, thanks for sharing, love to see old machines still in daily use.
Now I'd like to see a follow-up video showing you modding both an XT-FDC and a Sergey's FDC. :D
I've only been following the channel since the trip to Canada. Even just since then, the camera quality has gone up. The editing and cuts to B roll feel smoother and more frequent,.which is more engaging, and even the scripting has really stepped up. This is just blowing my mind when it comes to quality and content. Great video, super cool and informative. You sir, are crushing it.
I wondered about the weird TRS80 interface on other videos...but now I see they were right all along.
What a *TWIST*!
This finally explained to me one of the questions I've had for about 30 years now: why my very old XT hardware documentation about floppy drives seemed to be incorrect.
Thank you so much for not letting me die unknowing!
I REALLY need/want to get my Win98 machine to have 3 floppy drives for getting data to and from all my machines.
Another awesome video, very well researched and I learned stuff.
Only thing I'd tweak is the 4 drive IDE thing, that only became a standard thing sometime around the intro of the Pentium architecture, and it was not done for Hard Drive support, more for optical drives and other non-hard drive devices. When CD-ROM drives shifted from SCSI to IDE people starting realizing that a single IDE channel was not enough, and then later on when drives increased in speed it became apparent that having slower IDE drives on the same channel as the high speed HDD was degrading performance, so the demand became to add a second IDE channel on boards. So the evolution to 4 IDE drive support had not much to do with having 4 HDDs, more to do with performance and the desire to have multiple other IDE devices.
Especially that in a typical machine with one hard drive and one optical. If you were to upgrade the storage (let's say you bought a fancy new, 2 GB drive) with a single, 2-port controller, you'd have to either image over your installation or make a new one. And there would be no way to do that move while booting from CD, because that is where the 2nd hard drive sits.
Basically, out with the old drive in with the new, boot from CD, install the new system, CD drive out, old hard drive back in, move your stuff over, old drive out again and CD back in again.
But with 4 ports, you could just hang the new drive behind the old one.
The twist in the cable was introduced with the PC/AT and then carried over to the XT during its time of production overlap with the AT. Texas Instruments also used normal Shugart interface floppy drives with their controller for the 99-4 and 4/A using a straight through cable with all female connectors and special male/male connector PCBs to swap the ID lines for the two external drives while the single internal drive used a 34 pin 0.1" header to card edge cable. It's also possible to custom wire a cable and skip the little connector PCBs. Unfortunately TI neglected to make their floppy controller with double density support, leaving that up to the aftermarket. But there is a way to modify the TI controller to use 80 track 720K (3.5" or 5.25") drives as 360K single density. Most of the aftermarket controllers also supported 4 drives.
3:56 Apple didn’t need an interface *board* for its floppy drives: it had an interface *chip* . This was because it didn’t bother with actual hardware to do the encoding and decoding of the magnetic signals: this was all done in software, courtesy of that hardware genius, Mr Steve Wozniak.
In the 1990s, I decided to try and use an 8" drive on my PC, while keeping both 5.25" and 3.5" drives.
My first 4-floppy FDC has been a controller made by GSI, with 2 x 34-pin connectors on the board. My setup was then A: 1.2M, B: 1.44M, and the 8" got the letter D: and was set as 1.2M in the BIOS. An 8" is really a big 1.2M drive, but with 77 tracks instead of 80. I could format blank 8" disks with DOS, and the stepper would knock 3 times at the end after track 77. No error message on FORMAT, that's normal, but I know I couldn't use the 3 last "non existing" tracks. Still cool by 1994 to write data and hear the loud stepper of the 8" drive. They were well gone by then! The challenge was to make the home made adapter from th 8" 50-pin bus to the standard PC 34-pin floppy. The 8" drives were in an external casing with its own 24V power supply, which is different and bigger than the standard PC 4-pin Molex. I still have all my equipment today, plus I bought the MicroSolutions CompatiCard IV in the early 2000s. This is the holy grail of disk controllers, and it also supports 4 floppies. It came with their special 50-pin to 34-pin floppy cable adapter, so I didn't need to use my home-made anymore, that was quite fragile (it was a piece of art, connecting thin wires between the 50-pin female and the 34-pin female, and if one got too loose, I lost a signal and got an error). I was glad to get the PCB adapter with 50pin and 34pin connectors from them...
The CompatiCard IV is able to read/write FM Single Density, in particular the IBM 3740 format developped in the 1970s, which is 8", 77 tracks, 26 sect/track, and 128 bytes/sect. Although this predates the IBM PC, I was still able to read the data sector-by-sector, and take disk images, using the program ANADISK. The file size is 256,256 bytes, so 250.25 KB... I also got 86-DOS on that format, as well as early non-PC CP/M-86 versions from 1980-81...
Just a thought, but weren't there some early tape drives that ran off of the floppy controller too?
There were indeed. =3
Ah yeah those Colorado tape drives, never came across one yet.
They were a pain in the bum. Only certain types of floppy interface ran fast enough for them, and even then only on a good day when the wind was blowing in the right direction.
@@Alexis_du_60 Yeah! That's what they were called, for the life of me I couldn't remember... Even though I had one that I inherited from my mom's office way back.
@@orionfl79 I never had luck trying to find one, and the few I found had some weird gooey and sticky stuff oozing out of it... Probably the rubber rollers breaking down? I don't know for sure.
Funny you mention the PS/2, as the models 25/30/40 were indeed limited to 2 floppy drives, but models above that were not, eventho that did require adding controller cards.
For years I've had a PS/2 model 80 around which had 2 internal drives (2x 3.5" 1.44mb) and 2 external drives (5.25" 360kb and 5.25" 1.2mb). That was an officially supported configuration (I worked at IBM at the time and did support for PS/2 machines). This machine was used for archiving media, it also had an internal worm drive for storing archived disks.
However, support for those extra drives was provided by the option roms (and related settings), not directly by the bios.
Thank You!!!! That's a subject that has always bugged me and information online is very scarce.
Superb video as always! I tried doing the exact same setup as you but I used a BIOSless card. I did manage to get one of those DOS config.sys drivers working ... But really compatibility sucked and while the drive worked in DOS, disk imaging software had issues with the third drive. (1.2mb in my machine as well ) Even with your setup I'd imagine software like IMD still can only see A and B....
In this case I was using DSKImage, I've not made friends with IMD yet. Every time I try it it seems like I always have to convert images three different times to a format it will accept.
DSKImage just has you write out a string describing the drive as ID:Sides:tracks:sectors and it will send raw commands to the drive with that. So I set it to ID 2 with the rest of the values for a 1.2MB drive and it worked perfectly for me. I wouldn't be surprised if there is software that is hardcoded with 2 drives only or some other oversight though
The problem with a second controller is, for the most part I believe, that the TSRs for them attempt to remap the 2nd controllers drives 0 & 1 to the address of the 1st controllers drives 2 & 3. So if you use something that somehow by passes the TSR then it doesn't work. But I never even got the second controllers drives to show up in DOS, so there there's some speculation there.
@@TechTangents ah yes I've used DSKimage and that would definitely work. I end up with IMD because of its support of FM disk formats and also mixed FM and MFM in one disk which the TRS80 M1 uses. But of course no vintage machine uses a 1.2mb drive so who cares really! LOL. The detail in your video was so spot on -- the best explanation I've ever seen in one place so it'll be a resource for the future if anyone else tries to do 4 drives.
I never realized how lucky I was that TI used completely stock drives on the 99/4a until today.
I remember how unlucky I was that the FDC interface required buying the overpriced expansion box, thus limiting me to 2 standard cassette recorders and the 4K RAM in the Mini Memory module.
@@johndododoe1411 Not true! The P-Box came late, as users started having too many sidecars. There was a sidecar disk controller from TI, as well as several third-party controllers.
Man these old technology...is ine of my favorite I wish if some of these can be found in the market 😍
eBay. I sell this kind of stuff.
This was a lot of fun to see. Could you demonstrate more of that BIOS option menu in a future video?
I've always wanted 4 floppy drive support for the same reason you did. I have never found a 4 drive controller in the wild, though, so you lucked out there. I didn't know about the XT FDC either. I will look into that. I remember watching a video on UA-cam (but can't remember from who) where they had a motherboard with 4 floppy support in the BIOS, and he needed to use 2 floppy controller cars with configurable IRQ and DMA to get it to work. I think it was some 386 board, but I could be mistaken. I imagine that's even rarer than finding a 4 drive controller. The one thing that would be really neat is if something allowed this and also enabled 3 mode support on the 3.5 drive, for reading that odd format on Japanese PCs that used 3.5 inch drives, but ran them as 5.25 1.2 MB drives.
Ahh, the IBM PC AT It was the bees knees at the time. Mine had two HD floppies and two 40MB HDDs. I had reasons ... Mostly, I was a developer and having the source file on one HDD and the output on the other almost doubled the speed. Two floppies were for making copies. Again, speed was the incentive. In the case of the floppies, it made copying much more that twice as fast. I should get a PC, and XT and an AT ... and possibly a 386SX (I had good memories of one). I'm sick, aren't I? Especially considering I have a bout 30 8-bit systems and a PDP-11/74 cluttering up my 'show room'. How about a Micro-VAX????
Your collection is obviously incomplete. Change that!
Hey hey you're finally talking about something I knew before hand! Still gonna watch it anyways because I love the production quality!
One of my many Taiwanese clone PCs, based on the DTK Turbo 640 board, left the factory with two floppy controllers and 3 drives! One controller was configured in slave mode, which is an interesting thing to set up. The second controller was controlling the third drive, which because of the ancient hackjob of a BIOS and the old version of DOS I have to use to make that work at all, and the lack of a fixed disk controller (which crashes the garbage BIOS), the floppy drives are A, B, and C.
Funny enough, I've got some weirdo Asian import no-name motherboards going all the way up to the early 2000s (AMD Socket 462) which list a "Third floppy support" in the BIOS and will let you connect a third drive on a different drive select on the same cable. I've never come across the actual cable, but jamming some wires in a breadboard I did actually manage to see it work, at least enough for Windows to show a disk drive in "F:" (That particular computer has two optical drives).
Since most controllers internally support four drives, and since you can get BIOS extensions to make those extra two drives work, you should in theory be able to modify a standard diskette drive controller, or even an onboard one to allow four drives. Most off the shelf drive controllers you see in IBMs are pretty well documented Fairchild or Zilog parts or whatever, stuff you can find datasheets on without too much hair pulling
EDIT: Haha, you talked about it in the video. The only BIOS I've seen that supports a second controller is that absolute garbage Taiwanese clone BIOS, which doesn't even do a proper memory test. No EGA support either, MDA or CGA *only*. It's probably the least functional it could be to make the machine work, but it does have that one random advantage that it happens to work with a second address card. Supposedly it supports the same for video cards and hard disk controllers, but adding a second video card causes the machine to act very strangely (switches between the cards at random, think displaying half a word on one card and the other half on the other), and adding a hard disk controller period will cause it to hang on boot
Finding the jumper settings isn't terrible for most cards! Have you tried Total Hardware 99? Statson.org is a reupload with a more "modern" layout and lots of ads if you're more comfortable there.
th99.infania.net is where I go to get all mine.
Is your LS-120 drive really that unreliable? I've never had a problem with any of the three I have laying around, as long as you keep the heads clean and the rails lubed like any other drive it'll be just as reliable. The lack of direct hardware access might cause you drama, though. I have a lot more issues with iomega drives (ZIP, JAZ, ditto, Clik!, etc) failing and eating media.
I'm interested in the "CA9277B-21" card you mentioned in the video, would you be open to dumping and posting the BIOS extension on that card?
A guy talking about old floppy drives and all their connections and other differences for 18 minutes. UA-cam algorithm knows me too well.
Wow wow wow!! Thanks for this video :) Gotta admit, i like retro stuff in general, but floppies have a special place in my heart. My first computer was a ZX Spectrum clone, and I was so jealous at the time of the more modern machines that had floppies since it was so much faster than tape :) Then i got an 8086 and started hoarding a number of floppies, some of which i lost last couple of times i moved, but i still have a great deal around. Setting up one of my old machines to have 3 floppies + my IDE zip drive was an idea I had bouncing in my head for quite a while now. Maybe i can learn something from your videos. Anyway, sorry for the rant. Love your content! Cheers!
That was not a rant, it was sharing some ideas/thoughts, and should not be lookd down upon. Greets from a fellow Speccy enthusiast. :D
I had an after-market floppy disk controller for my ZX Spectrum - I think it might have been the MGT DISCiPle one iirc - not sure - it was over 30 years ago :) but I had that connected to a 3.5" 360K single sided floppy drive. It was an amazing step forward from loading games off cassette tape, that's for sure :) and it also has a so-called "magic button" that you could press after you'd loaded a game off tape and that would dump a full memory snapshot of the RAM to disk, which is how I put games onto floppy. Since I had a 48K Spectrum at the time, I was able to get 7 games on a single disk, which was pretty damned impressive at the time (around 1988-ish)
Mildly scared for the table wobble on the video. Very interesting video :)
Deffo needs sturdier desk
Incredibly informative video. I love deep dives like this. I wonder how 5.25 disk duplication worked on a large scale back in the day - though conceivably those machines wouldn't actually "read" or have a drive letter they would just write...
Those kinds of cards with extra controllers but no BIOS are probably useful for like mass disk copy operations where you write some custom software to address the ports directly.
Awesome video but a bit scary to watch. With all that table wobbling I was scared that the computer would fall over.
I suck at soldering, but building a flux engine is easy enough and the software is kinda neat. Fully recommended.
c: I'm more of a / person.
dh0: rules all!
@@MariaEngstrom Sure thing Amigo.
Not to mention way less limited.
Oh, b:have
Me too, but for some reason getting an external floppy drive working on Linux is super finicky.
I like the video because it's hard to keep up with everything. The XT-FDC and Sergey's FDC is going to be worth checking out. The twist in the ribbons motor control is not an IBM thought, it's actually from hacks that were used to help techs swap out floppy drives and reduced the time to switch. The manufacturers picked up on it and adopted it as standard practice. The two common reasons we needed several floppies were 1) copying floppies over several drives at the same time reduced the time it took to copy floppy to floppy. If a person looks way back in the old catalogs they could find "towers" much the same way people can find cd towers. 2) more commonly, it was easier to load software by redirecting a drive already loaded with the next disk rather than simply flipping floppies. Most floppy controller boards had at least IRQ jumpers that the controller can be assigned, the real problem was figuring out which IRQ was free. While the on board bios supported A and B drives, it was largely because the controller was on the board, and it was common that the default system files were on the A drive, the B drive was included since the controller supported two drives. More floppy drives got an extended letter after the hard drive mainly because the bios support for four hard drives (in most cases) meant they had priority over the next available drives that is not in the bios. C,D,E,F were often reserved for hard drives unless there was one HD controller on the board then C,D. After that then the installer had to manually assign the drives either by pin or in the config,sys working with the software driver. The reason Manufacturers reduced the inclusion of floppy drives over the years was that by the time CD's started being used for software storage, the writing was on the wall for floppies.
BIOS doesn't assign or use drive letters, they simply referred to floppy drives number 0, 1, and higher, plus hard drives 128, 129 and higher . BIOS user interfaces were added later and used the DOS letters for familiarity . I'm unsure hoe the new BIOS interfaces like ABIOS and EFI index drives .
I like the outro of showing the machine working on its own. It reminds me of the end credits for episodes of _Are You Being Served?_ when they would show product displays from earlier going haywire..... except, we don't want to see PCs actually going bad, unless it's a gag setup, like a smoke machine with lighting tricks.
Dude I'm having a heck of a time getting one 5.25 floppy working in winxp. The bios supports and is selected to 5.25. The drive powers and spins but doesn't seek. Idk man maybe the drive is broken. Anyways awesome video you've helped thousands of people.
On modern computers I often use A: and B: for removable media, usually SD/MMC or MemoryStick cards.
Me too! :D
I think that's the first time I've seen someone populate all 6 bays in a tower.
I do seem to vaguely remember the 4 drive set up for TRS PC's, but never had experience as my only TRS machine was a CoCo2 and even a single floppy was out of my price range.
I think if I ever got into what they now seem to call "retro computing", I'd be one of those guys who would only use old media for kicks and for day to day fun I would use those kits I've been seeing that allow modern flash hardware to mimic floppies.
Even back in the day, one of my goofy side projects was to put win 3.1 on a CD to see how fast I could install it. It seemed stupidly fast to me at the time, lol.
Many controllers supported up to 4 floppy drives. The big PC companies didn't often support more than 2. But many of the generic clones that were made from a collection of parts did offer up to 4.
Some machines used 80 track DSDD 5¼" formats with BIOS routines mapping sector sizes like modern hard discs do. This pushed capacity way above the PC limitations .
Adding a second (or third or fourth) floppy controller works perfectly with Linux as long as you supply the io-Adress and IRQ on the kernel command line or the module command line - disclaimer, I am talking about kernel 1.0 or 1.2, not sure if this still works today. In fact I once took an "non-configurable" floppy controller and rewired the ISA connectors adress lines so the IO landed in a VERY strange place. Worked like a charm in Linux as fd2 and fd3 - I might had to mknod the devics manually under /dev/ but thats trivial. I am not sure if the minor nodes where like 0,1,2,3 or 0,1,64,65 but I think the later was true and it was visible from the kernel boot log. In hindsight FreeDOS could support that too as I remember it has an option for additional IO-ports for floppies. Maybe a seperate DOS driver could do the same but then I am not aware of anything like that.
note the floppy controller from the 70's ran from 40 pin scsi device, the late 80's to early 90's floppies seen from windows 3.1-win 8 ..
with the major shift to pci-e you have major issues in connecting up older hardware unless someone creates a sata line type floppy interface
I fucking love Nextcloud. Been using it for several years, hosted on my own server. It's been immeasurably useful over the years beyond it's usual cloud backup services
No picture of the inside with all of the IDE cables snaked around each other? Akbukuku please :(
I never knew that you could get 4 floppy drive support or the cards to make it happen. Good bit of info that pal! i always thought IDE and SCSI were the ones to have for extra drives.
11:53 i actually quickly turned my head arround when i saw that reflection of yours.
The additional MR BIOS (Microid Research) has support for 4 floppy drives natively with two 2 floppy drive controllers. It replaces the original bios on the motherboard
IMO leaving the unneeded (for almost all people) 4 drive support is similar to the use of 2 digits for year representation. It doesn't require extra info/worry/etc. when its not needed in most cases (over than when you switch centuries... or are doing copying between formats in your example).
+1 for making a FluxEngine at some point. I basically only ever used 'boring' 1.44Mb IBM PC floppies in my time, but still I built one to backup my collection just because it was a cheap and easy weekend project, and modern USB floppy drives are just garbage. You actually come across more exotic discs, so you have even more reason to have one around (even if you do have the proper hardware to read them).
You should add a 720K 3.5 inch drive, because although you can read 720K disks from a 1.44 drive, writing disks does NOT work reliably (supposedly due to magnetic strength or something)
It's the other way around - writing to a 720k disk from a 1440k drive is reliable, but not 720k drive to 1440k disk. The magnetic impedance of a DD disk is lower than an HD disk, so you actually need less of a magnetic field to permanently flip the bit. The drive head of an HD drive has a higher magnetic field strength.
a few years ago I found an old PC almost like this with 4 drives in it (I forget the configuration, but it was a huge tower PC from the early to mid 90s I was guessing). It was $50, I wish I got it cause it was pretty awesome.
1:10 That was actually pretty hardcore dude 👏😲
You disappoint me Shelby. If you're not going to do a build with 8 floppy drives who will?
Conversely, as more and more motherboards drop support for floppy drives entirely, it's possible to assign the drive letters A: and B: to one or two hard drives / SSDs / USB drives et.c.
Very interesting video by the way; I was aware that many FDCs had support for up to 4 drives, for example the uPD765 which is a very common IC - but again with the caveat that it can only support one /Motor-On signal. Whether the floppy drives themselves can decode the 2 Select lines to 4 individual IDs is another matter altogether, though.
Had a card reader on drive B for ages now, even on a machine that comes with floppy support.
It is possible to install more than the standard two (IDE) floppies, in that you use SCSI FDD, internally or externally, connected to one or more SCSI host adapter.
Thanks for the video, I was always fascinated by that 4 drives theory (never seen more than two though). But please get a more stable desk :D
Good old I/O cards. Back then I got one from a friend and plugged into my Pentium MMX, so that there was another IDE channel, floppy channel, serial ports etc. I can't exactly remember (20 years back) what happened / whether it worked or not though.
I think now we can just use 4 USB floppy drivers easily.
LGR is salivating right now.
I'd like to know how we used to install a master and slave HDD in... say, a 486, or a Pentium. When my HDD was dying, a friend gave me a second HDD, but I couldn't get them both working on the same machine at the same time. Thus, anything I wanted to save from the dying drive, had to be copied by 3.5" floppy as it was my only other option. I did get most everything transferred, but not everything due to the size limit of the floppy.
I did some digging into the logo and and the model number on Shelby's card. I found a 5 year old forum post that mentioned the company called "Relialogic Corporation PTE Ltd." out of Singapore. I'd take it with a grain of salt, but it's all I could find after searching for well over an hour. I did uncover other cards that are suspected to be from the same manufacturer.
Ohh man no seek sound test on all the floppy's. Love that sound. Still good and entertaining.
Would love to hear a four-floppy computer boot.
BRRRRdrrr 😀
bDRRRRddrrr 😃
BARRRRdarr 🧐
HRRRRdrrr 🤪
...
*BEEP!* 🤟😍
Indeed, with a dedicated 4 drive controller with its own BIOS extension, making a 4 floppy drive system isn't that hard.
I have made such a system myself. Demo video is also on YT.
Using 2 separate controllers with the secondary at port 370h is the real challenge though. It can be done if IRQs and DRQs are different between the 2 controllers. Then there is either BIOS support or an OS driver needed to access drives 3 and 4. Being unable to find a DOS or Windows driver for this, I used the BIOS extention from Sergey's FDC to realize this. This works, although it isn't very fast and stability in Windows 95 is an issue. However, unlike with a 4 drive controller, having 2 separate controllers allows one to read or write 2 different floppies in parallel in the same system --> try to achieve that with a standard 2 drive system; the first drive pauses the moment the second drive is accessed.
And on another note, the 1.2mb drive versus 360kb drive... that is a problem when overwriting a floppy formatted on a 360kb drive with a 1.2mb drive. The result of that would not be properly readable. But in itself, a 1.2mb drive can read both 360kb and 1.2mb 5.25" floppies without problems.
On my 1983 HP 150 Touchscreen the 3.5" floppy drive is B: and the 15mb hard drive is A: (unless you have it boot from floppy then the other way round). The joys of early DOS compatible but not PC compatible computing! It runs custom DOS 2.11 BTW and the floppy is not 720k but a 710k custom format so some special dos drivers need to read/write to them.
I'm going to have to look into my old 286 at my parents' place because it has 4 floppy drives in it! 2x 5.25" and 2x 3.5", each size format with a DD and HD drive! I never looked into why or how all drives were supported at the time!
You might get the secondary floppy io address working by installing an xt-ide bios in a network card.
That logo on your card was for a company called patriot. They closed shop forever ago she a new company is using there name. I have a few old cards made by them.
Do you mean memory-cards? This isn't Patriot, it's Relialogic.
Commodore Amiga supports 4 floppy drives natively, DF0,DF1,DF2,DF3 in any order, 1 internal, 2 internal, 1 int 3 ext, 2 int 2 ext. ect...
Amazing facts. I always wondered where is B drive installed 😂
Lamo
Wow, what a flashback. On the old atari ST you could use pc drives in it. Including the external boxes. And yeah you could mess things up if a drive was set at ID 3 or 4. The teac 3.5 drive 0 & drive 1 pins were binary, so it was actually a binary 0-3. For backwards compatibility. I really screwed with some friends back in the day by setting drives to 2 or 3 aka drives 3 & 4.
I have never gotten the chance to obtain such a big full-sized ATX case, especially one made of steel. Gloriously heavy indeed, and allot of space to put a smaller motherboard inside (or two!) and two power supplies (hard disk cavity was massive enough!), along with six (6) cooling/exhaust fans. Yeah, that's still my damn dream. xD
Current machine runs GNU/Linux (mint), windows 10 on a secondary drive (fucking never use it lol), has 24GB RAM (DDR3) and quad core AMD Athlon(tm) II X4 620 Processor at 2.6 GHz along with AMD HD series graphics.
Nice video, also wanted to mention i actually tried to sign up for linode using your code but my account was immediately banned i tried contacting support and they refuse to share any information as to why they did that, i checked all my information and they basically refuse to help in any way. So yea quite an unfortunate experience.
They, IBM, released a expansion chassis for the PC and XT where you could put in more drives.
Just FYI - The the hard drive is "C" is MS DOS doing it on purpose. That behaviour didn't start until MS DOS 5.0. Earlier versions would've mounted the floppies as ABC, then done the hard drive partitions starting at D. It's not actually related to what was detected when.
Great video, and loved seeing that IO card. I need to find one myself!
How do tape drives like the QIC 80 fit into all this? They were usually directly connected to the floppy controller with a special cable which in turn had a connector to which the floppy drives were connected. Would this mean the QIC 80 drive would actually be adressed as the 3rd or 4th floppy drive?
Yes, I still have to do that on some of my older computer to back up data.
I still have my TRS-80 MOd I with 4x floppy drives. I dare not plug it in lest it burst into flames -- I'm sure the components are unstable, especially the caps. It hasn't been powered on since the late 80s. I just can't bear to get rid of it.
This brings up physical vs logical. I remember having to deal with Windows assigning drives then having to use a batch file to correct that
When 98 addresses by the order of the ports they're plugged in, so if you ad a disk it can break all your shortcuts.
Nice video ! I have XT clone and as usual it support 4 Flippyes configured with jumpers on the motherboard. The question is how to configure it for no Flippyes at all, it have to be 1, 2, 3 or 4 , but not have option for 0 . It is annoying to press F1 every time on the POST, beciuse I have no floppy controller and floppy drives in the system
I had an Amiga that could take four floppy drives(drive 0 was internal to the computer, drive 1 was an external which had another external connector for daisy chaining in drives 2 and 3), and even before I got the hard drive, there was never an occasion where I'd need more than 2 drives, other than installing a new program. The cost wasn't worth the use case.
Just picked up a Tandy 1000 tl/2 with three floppies. The hdd still comes up as c, but the third drive is D.
I’ve got some of the LS120 drives in my Silicon Graphics Indy workstations.
Love your videos!
watching that giant monolith of a case sitting beside him rocking back and forth every time he moves makes me slightly uncomfortable.
Tech Tangents: A and B are reserved for floppy drives
Me: but I can reassign in Windows my drive to A or B (meme)
meeme
Mehm
Maymay
Or subst a folder to a drive letter
amiga can 4 floppies and read endles formats on it
also the IDE can handle more hard disks then on the PC ...
Yep, my Amigas and C64s would have more than 2 floppy drives connected on multiple occasions. Why might someone routinely need more than 2 floppy drives? er.. um.. yo ho yo ho... ;-)
Uh, ... Cool.
@Mr Guru yes stock without a little easy midification 😁
@Mr Guru I have a nice little device in my A1200 which allows me to use up to 4 IDE drives at once; one port has a standard 40-pin connector, and the other has both a 40-pin and a 44-pin 2½" connector, but only one of those can be used at a time.
It would be a interesting excersize to do something like this but also with optical drives.
Hello I loved the video and even more the case of that pc. Can I ask what kind of case is that?
Alright, since you're quite knowledgeable here, you might be able to help me out. I'm looking to make a PC like the one you've got (entire front panel filled up with stuff, maybe even six big bays and two small ones) that'll allow me to read different and sometimes exotic types of storage media, but also be reasonably useable for today's applications. That's why I've been thinking of a core 2 duo era motherboard. The problem is that they a) don't have ISA slots so I won't be able to use an old ISA floppy controller with them and b) even if they have built-in FDD, due to the period those can usually handle only a single FDD drive. In addition to having both a 1,44 MB 3,5'' and 1,2 MB 5,25'' drive, I want that PC to have a dvd-rw, a 750MB Zip drive, a 2,3GB magneto-optical 3,5'' drive (50 pin SCSI) and a multi-card reader, in addition to free USB support for moving data to newer devices.
IDE and SCSI are easy - there are PCI controller cards for those, so I'm not worried about them. I also know I could just hook the 5,25'' drive into the FDD slot and convert the 3,5'' drive into USB via an adapter and plug it into one of the motherboard's USB pinout. The 3,5'' drive will detect just fine that way.
There are also those "combo drives", like the ones Teac and Epson made, that combine 3,5'' and 5,25'' drives in a single 5,25'' form factor - and they use all the same connectors as 3,5'' drives. If I could get my hands on one of those, I could probably make it work with a mobo that only supports a single FDD drive. The question though is - would they be recognized by the system as both A and B, or just A, meaning it couldn't have two diskettes inserted simultaneously?
The controller card is from Promise Technology and they still sell 4 floppy controller cards.
i assume mainboards often came with 2 ide ports because the single controller supported 4 drives much mike modern high end Z490 boards still have a ps2 port
having a floppy drive as C: would surely cause some interesting software problems :P
Probably. But did you know Windows can be installed on any drive letter (at least before Vista)? The NT based ones can even boot with absolutely no C drive. I've had this accidentally happen when installing 2000 or XP when there's already a formatted drive in the system.
@@eDoc2020 i took a class on OS troubleshooting that involved managing five separate installations of NT on the same hard drive. it was quite the nightmare. parts of Windows and some Windows software expects Windows to be installed on C:, and will behave very strangely if that's not the case.
@@iceowl Even with properly behaved applications the different Windows installations will use the same 'Program Files' directory and you'll get lots of mismatches. Now whenever I need different Windows versions on the same drive I'll use a different partition and either hide the other partitions if I'm booting the installer from CD or delete/modify the migrate.inf if I started the install from within a different Windows installation.
Man they are so difficult to find, those 4 drive controllers. Really hoping there's enough of a push for these that someone comes up with a new solution.