All you never wanted to know about 8 inch floppy drives
ฝัง
- เผยแพร่เมื่อ 8 ก.ค. 2024
- We connect an 8" floppy drive to a PC, learn the 11 ways they are different from standard PC floppies, and even design an adapter and make it available for all on Tindie.
Chapters:
00:00 Intro
01:20 My 8" drives come from an HP 9895
02:37 The IBM 8" floppy and its media
06:03 Antoine's 8" floppy adapter
07:06 Booting my PC from the 8" floppy
08:24 8" drive restoration and bring up
11:08 Making the prototype cable adapter
20:16 The 11 quirks of 8" floppies
20:52 Single sided vs. double sided
21:48 Write protect works reverse
22:52 Four address wires!
24:56 Head load signal
25:41 Door lock signal
26:38 Disk ready vs. disk change
28:02 Track 43 current control
28:37 Pull up resistors
29:28 500kHz data rate
30:07 FM modulation support
30:49 ImageDisk and Omnidisk setup for 77 tracks
32:52 Formatting an 8" Floppy
34:07 Using the floppy with Windows
35:25 Playing Donkey Kong from the 8" diskette
Antoine's 8 inch floppy adapter on Tindie: www.tindie.com/products/silic...
Adrian's Digital Basement video on the 8" floppy: • This is how to use an ...
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I love how we are complaining about faint coil noises in our graphics cards nowadays, and this thing simply sounds like a tractor is pulling up the driveway.
Well, I’ll have you know that there IS a tractor in my driveway! (no, really… it’s a nice red Massey Ferguson. Yes, I live out in the sticks & rattlesnakes).
@@darkwinter6028 Does it have a 34pin interface or just an analog driveshaft?
The sound of a well maintained floppy loading is kinda soothing to me. When I was small, I could only dream of owning a floppy drive, now people mock those beautiful things.
@@Jenny_Digital Yeah… and there’s something special about the sound of a 1541 that other drives for some reason don’t have…
@@darkwinter6028 Oh, you mean the hammering against the end stop. This was done to home the drive to track 0, and later models stopped doing it that way.
Check your alignment with those drives.
I have done a lot of tinkering with those IBM drives in the 1980's...
The drive you show at 2:48 is the actual drive that was in those controllers and computers of the day to load the microcode.
It was behind a door on the cabinet and was only supposed to be accessed by the Customer Engineer (a technician that usually was resident on site at important installations to quickly repair things).
Note that this type of drive has no front bezel, it just hinges open to insert/remove the diskette. There is nothing like a door lock, just a bulky manually operated catch.
Also no things like a disk activity LED. The "early drive" you show is actually from the later use of that diskette in data entry stations (where data that would normally be punched on cards was written on these floppies). Those were the first ones that had front bezels, LED, door locking etc.
The stepper motor is very slow, like 50-70ms track to track access time. It is linked to the head movement via a Malthezer Cross, a linkage that locks the heads in place when the stepper motor is not energized (it transfers rotation in the direction motor->heads but blocks rotation of the heads when the motor is not energized).
The step mechanism is VERY noisy! You would not hear it in a typical mainframe server room of course, but you certainly hear it when used at home (on the next floor, even). Compare to a teletype :-)
The drive had a proprietary IBM interface connector with signals similar to the later Shugart standard, but indeed with 150ohm pullups. I made interface boards that converted from that standard to the Shugart standard, which mainly consisted of beefy TTL drivers to drive the pullups.
In those days I had a TRS-80 model 1 and I used NEWDOS/80 2.0. It had sophisticated configuration of the drive parameters. You could arbitrarily set the number of cylinders, sides, sectors per track, steprate, and even "double step".
So my interface board included a divide-by-two on the "step" signal, I configured "double step" in the operating system and set it to the slowest steprate so the double step was slow enough for the drive to keep up.
I modified the floppy controller to have 500kHz mode (as opposed to the 250kHz used on 5.25" drives) and with all this I was able to use this drive in NEWDOS/80 as a standard drive, but with more capacity (the standard drives for that computer were 5.25" single sided single density 35 tracks!)
I still have a couple of them in storage, 3 in a big cabinet with powersupply and 50pin ribbon cable. I intend to power it up sometime and use GreaseWeasle to read what is on them.
Didn't the 23FD also have the sector mark at the outer periphery of the diskette rather than close to the hub?
I had 33FDs and 43FDs (now gone long ago) and somewhere an interface adapter circuit drawn by some of my Dad's IBM colleagues back in the late 70s but I'm stuffed if I can find it now.
I have since acquired another 33FD off eBay with the same intention as yourself of using a GreaseWeasle to drive it.
@@1944GPW It is too long ago to remember the exact details... what I know is that I have a single-sided drive and two double-sided drives. The latter are much faster (in stepping), but the construction is the same open frame as the 33FD. I think those may be the 43FD, yes.
And I have a big stack of diskettes, and don't remember any issue with using them.
The double-sided drives of course have two index hole detectors.
I guess your dad was an IBM CE as well. It seems a lot of these drives were going around, suddenly they had to be replaced with a spare :-) And the diskettes were always in good supply because the updates were sent around on new diskettes all the time, making the old version diskette available for re-use in the hobby.
Wow, fascinating, that’s some interesting deep info! (First I’d heard of GreaseWeasel, I’m gonna go look it up!)
"You would not hear it in a typical mainframe server room of course"
I wish I could have been there! (that took a google to get right for a European. (this one only an autocorrect). Did not bother with this one!) ((That's how picky using a disk drive is, no matter the format!)))
We embraced the noise. This "everything gotta be silent" crap is ridiculous. You could tell a lot from the seek sounds
I spent far too much time shuffling 8" floppy drives in PDP-11s. Lots of Shugart floppy drives, they were built like a tank and very reliable at the time considering how we abused them.
Magnetic Peripherals was later spun off from CDC, becoming Imprimis, and still being based in Oklahoma City. It eventually became part of Seagate who adopted CDC/Imprimis' practice of using the names of birds and predatory fish to name their storage products.
Between this and Adrian's video we have so much more information that is easily available now!
Thanks. Here is a link to Adrian's video for reference: th-cam.com/video/TfEzjcG_0gs/w-d-xo.html
Combining this with Adrien's other floppy disk writing video provides a ton of info
th-cam.com/video/fRZVlsxSDw0/w-d-xo.html
In IBM San José Engineering lab, we wrote the 8” diskettes for the 2835 microcode, in a modified 2841 File Control Unit, with the required floppy microcode on modified TROS tapes.
We had a special 8” diskette attached to the 2841 frame, that had R/W capability.
This is the way we tested microcode and sent patches for the 2835/2305 high speed drum facility (which was actually made up of many disk platters, with multiple heads for track on each platter, and no physical head movement.
You can also specify 77 tracks with the DOS FORMAT command by using the /T:77 parameter.
Nope. Won't work. DOS consults the BIOS parameters, which only allow for 40 and 80 track. The only exception was an early version of DOS for a specific manufacturer. There IS a TSR utility out there called 8FORMAT, and it does just that, hooks and intercepts the BIOS parameter table. I have it working just fine. Otherwise, most 8" drives will simply disengage past 78, though DOS will still think those last 3 tracks are available. (Using the 1.2M 5-1/4" definition. (80 tracks, 500KHz data rate, 15-sector, 512-byte per sector.) NOTE however, that if you run LINUX, the BIOS parameters are not used. FDTOOLS includes the SUPERFORMAT utility, which CAN do 77-track definitions.)
Excellent!
I love seeing more CDC floppies out and about. The 9406 is actually what I needed for the Centurion since it supports seek pulses as fast as 3ms, but the 9400 that I bought uses a different type of stepper mechanism and only supports seek pulses as fast as 10ms. We had to do a little microcode editing on the controller card to slow it down.
But, I've spent so much time with my head buried in the 9400, I've never actually seen what the 9406 looked like. It's really fascinating how much the CDC/Mag Peripherals design changed in such a short time!
I love how it seams like every other 8inch drive out there is the one that would have worked perfectly, and you just got super unlucky with the one you bought
David if I end up with extras 9406 after repairing the pile I have it has your name on it!
"How should we name this amazing achievement in data storage technology? Well, it's a disk, and it's floppy... floppy disk?" I love how scientists and engineers name stuff :D
It was named that way to express the difference between it and a hard disk. Up to that point in time removable disks were stacks of hard platters.
Well it’s not hard….so it’s floppy. I suspect some sniggering took place at the naming😂!
There were two more types of floppies:
Hard sectored, which had a physical hole for EACH SECTOR in addition to the index.
Soft sectored, with only one hole, the index as mentioned in the movie.
(Personal knowledge, worked with both types).
I'm not saying that hard sectored are kinda rare... but I had ONE once sometime back in the 80s.
When I was a little kid, my dad resurrected an old computer that used hard sectored 8” disks. Since most of the disks we were able to scrounge were soft sectored, we built a jig to punch the extra holes. I fondly remember very carefully disassembling disks, punching them, and putting them back together. Some were really difficult to get apart, but others just had a few plastic spot welds that you could pop and weld back with an old soldering iron. You had to be fairly precise to get them to work reliably.
Very not IBM though... [Edit: another fail! IBM’s original Minnow drive *did* use hard sectored discs! See follow up video where we recover one sent by a viewer: th-cam.com/video/WkzPvTQSIgM/w-d-xo.html ]
@@CuriousMarc I believe the controller for the IBM 3600 point of sales / teller terminals used a hard-sector disk. I vaguely remember this from installing them in the late 80's at the bank I worked at. That time right before just about every one and everything switched to PCs for back-end generic hardware and did the 'custom' stuff in software.
@fredinit Well of course hard sectored floppies did exist. But for the life of me, I cannot find a valid reference for any use by IBM of hard sectored diskettes. [Edit: now there is! My own video on IBM’s very first Minnow drive, which uses hard sectored diskettes: th-cam.com/video/WkzPvTQSIgM/w-d-xo.html ]
Lovely to see the Dolch making an appearance again, mine has had a two year sleep but I should really wake it up.
Thank you! I was maybe 10 (1991) and my father took me to an auction at a local community college. There was a desk with a terminal built into it and I’ve had the shape and screen size burnt into my memory but could not for the life of me place it. I could never find any information about it. You showed an image of an IBM 3470 and that was it exactly! I even remember they had another system that was two bolted together that shared an 8 line display?
Anyhow. Thanks again. I finally know the name of that amazing looking terminal I’ve lusted over for over 30 years!
Because the high cost of electronics, they used mirrors to split one CRT display for two operators.
Haha - this brings back memories - I was a DEC service engineer in the mid 80's, some pdp11's I looked after had RX01/RX02 8 inch floppy drives and a few pdp8s did too. They made a lovely clunking noise! I seem to remember they used pre-formatted IBM disks, and I think they could be read on an MS-DOS system too.
8" drives were already on the way out when I got interested in computers, but my first system had one attached (originally for data interchange between clients' older systems and the computer). You don't look a given hose... especially when said horse comes with a one cubic meter crate full of 1.2 MB 8" disks and your allowance isn't enough to cover a box of 5"1/4 disks per month. So for a couple of years, I used this drive a lot. Still works, btw.
Carl…, we do miss him 😢
This takes me back! Those good old days where sometimes stuff worked, sometimes it didn’t, and sometimes you used the wrong interface and the whole thing went up in smoke. Still there was something special about using things like my first computer, an 8086 I built from dumpster parts with a 256 color 8-bit VGA card, (or 6809s and HC11s used in very early car ECUs in classic GMs), not to mention the family C64 as a kid and the Atari console my brother had, or the TRS80 that sometimes saw action. Much more interactive time where you still had to do more than just turn it on to use it.
This brings back memories of the late 80's for me . I spent many hours putting in circuit nodes for a Gen Rad bed of nails tester. We'd save all our work on 8 inch floppy's and then at some point we'd transfer the files to a DEC main frame via a 1200 baud modem. I remember when we needed a fresh floppy you'd have to see a "gate keeper" guy that would dole them out sparingly. By today's standard these we're overbuilt and made them very survivable , yes you'll still have to replace components that normally succumb to deterioration. Great video on a nostalgic subject. 👍
To make things worse, there had been some drives which used a binary addressing scheme on the DS jumpers to allow up to 16 drives. Those resistor packs are termination resistors that should only be present on the last drive (floppy cables can be LONG), that's why they are socketed. Great episode and for the first time I did not learn something new, but had a pleasant summary of things that drove people nuts 40 years ago already.
All you never knew you'd like to know about 8 inch floppy drives, I've really enjoyed this, thanks so much!
Ohh, this takes me back to early 1982, when I upgraded my build-from-scrap-parts apple-2 clone with an SVA ZVX4 8" floppy controller, to get some more capacity for cp/m. If I remember correctly, the drives I got used, where also CDC drives, ds/dd. I almost failed at figuring out how to set all the options and jumpers to get everything working - this was all new to me and I was just 17 :) 8" floppies quickly fell out of fashion at that time here in Germany. With the massive amounts of S-100 machines using 8" floppies in the US at that time, things where different in the US. In Germany, we never had a big user base of 8" drives, instead the whole home computing notion startet, when 5,25" where already taking over due to them being massively cheaper.
Another proof how brilliant the internet is - I would have sold my kidney for this video at the time (which I had to do in the first place, to get the drives and the controller).
Always love seeing Bob - Mr. Fancy Pants.
I’m in 8 inch floppy heaven.
Because, you know… the format is dead. But here, it will go on forever.
Actually, extremely happy in this crash lesson, because i haven't worked with these in eons and i'm gathering parts and bits to un-defunct an older computer i have.
wow Our company had a lot of these large 8 inch floppy drives and they worked fairly well. The big thing was pre internet days to track down parts and information. Grrr. 😎 Thanks.
Oh man that sound at the end takes me back
Back in the ‘80s, when working at HP, I wrote low-level code to recover data (written in an incompatible format) on 8” disks using a 9895. Good times 😊
Thank goodness I missed both 8 tracks and 8 inch floppies. At one point though I had a ton of 1.2 meg floppies. There was a time in history when that was the most economical archival storage format. I never had reliability problems, either.
5.25" floppy drives came when someone became more honest about their 8"
That takes me back to the late 80s when we'd back up our AutoCAD drawings onto 5.25 floppy disks. Never had to deal with the 8" drives, but it was interesting learning about them.
I remember there were also floppy disks with many index holes, including two closer together that marked the primary index. These were used in early personal computers such as Altair.
The ones with many "index" holes were made by Memorex. They had 33 holes I think. One for the beginning of the track and the next hole marked sector 1 followed by a hole for sector 2. Thus they had more sectors per track compared to the IBM standard. We used to called these "hard sector" disks where IBM was "soft sectored".
The multiple index holes indicate a hard sectored floppy, used in Northstar systems for example.
2:01 - A grey bearded nitpick here: HP-IB was standardized as IEEE-488 GP-IB which indeed saw quite widespread use, but mostly in instrumentation. A metrology lab I work with still uses it, and one of the more surprising uses was as peripheral bus for Commodore (then CBM) PET series of 6502-based microcomputers. One of such peripherals was their dual drive intelligent 5,25" floppy unit (it contained two 65xx processors in the role of microcontrollers, and communicated with the host using a very high level ASCII protocol.)
Weird.
In early '80 I was working in a company that used Ieee-488 bus to connect disk and tape units to the central unit.
This solution looked a bit weird, but at that time 488 was the only "system" bus interface available and well defined, and in the hope that other manufacturers of mass store could have adopted that solution, 488 was chosen.
The most astonishing feature of those controllers was the use of AMD bit slice architecture, which was 32 bit wide for the instruction size and operated at 4 Mhz! Control boards were wide and completely filled with a lot of components.... a nice view for an hardware engineer like myself!!!
Bit slice was an amazing architecture that allowed a design of a CPU with a proprietary instruction set and different sizes for data and instruction paths!
It was a lot of fun, but an assembler program was needed that turned the "mnemonic" Assembler text into binary values that were then loaded into the bipolar proms ( typically 4 or 8 kbytes!!!) that were not cheap at all!
@@sauronbadeye 👍
Woot. Yay I’m in OKC. Glad some cool computer history from here found its way to you. :)
Marc, There were also several types of 8-inch floppies that were hard sectored with multiple index holes punched in the media.
Many Broadcast Character Generators and Graphic Still Frame Stores used this style of 8-inch floppy for many years.
A Dolch! Loved that machine even though by the time you'd carried it all the way through the airport it felt like you were taking your anvil on a business trip.
What a ride, thank you for documenting this !
The long awaited sequel!
I’m not even into computers and this is fascinating. 👍🏻
Thanks for providing all the details on 8" floppies! I had one on a CompuPro many many years ago.
In late 1979 I started my design of a floppy disk controller for a new line of computer: at that time I worked for the most prominent European Company in the field of Information Technology, and the floppy was the only mass storage unit available when mass production started: hard disks and tapes came later on...
When the design was completed, it could control 4 8 inch unit and 2 51/4 unit: these units were manufactured by another division of the company and had an interface which was very similar to the Shugart interface.
I recall now that I was using the same kind of "twisted" cable for 5 1/4 units that was shown in the video, not only for the unit selection lines, but including the two "motor on " control lines... ( those that started the spindle motor...).
The controller was able to handle many kind of media including the so called Double Density recording scheme ( or MFM = Modified Frequency Modulation) but the data format complied with an European Standard Ecma, which provided 256 bytes per sector in place of the 512 bytes, which was more efficient.
In my case the maximum capacity was 1 M bytes instead of 1.2 M bytes of the 512 bytes/sector format.
Basically one byte was made of 8 bit cell, each lasting 2 microsecond for a total 16 microsecond per byte at nominal spindle speed.
The formatter ( the logic function that controlled read and write operations) was based on a NEC 765 chip, which was the most popular part at that time..
One complication of my design, was that the
System Bus was 16 bits wide, and so, when reading, two bytes were stored into registers , before being transferred into the System ram using a dma operation.
To keep the Central unit as simple as possible, in an attempt to cut down costs, there was no centralized dma but each controlled that needed dma operations for data transfer ( like disk and tape), had to implement its dma interface which was cumbersome and rather complex.
As a result the price burden was shifted from the Central Unit to the peripheral controllers, a very very bad choice!!
Other problems that affected my design, were troubles at the system level: randomly a dma access to the memory completed with time out errors, and later on I found out that the problem was due to reflections on signals, since the backplane was not properly terminated...
Other critical area was the so called " Data Separator" which basically " separated" data transitions from auxiliary transitions, when reading data in MFM mode...
My first attempt to use a state machine with an 8 mhz clock to "separate" data, was a failure, especially when reading a 8 inch diskette, which was more critical than a 5 1/4 diskette.
Only a far more complicated approach, was successful: all the logic circuits were then squeezed into a gate array which I designed in Texas Instrument, Houston, in the late summer of 1981...
And that's all folks!
the peculiar thing about the PC floppy interface is that it was made so "simple" compared to the rest of the machine. It's super complicated to change any configuration on the 5150, 5160, and 5170 models and if the expansion cards don't match the IBM originals the machine won't work correctly. Then we also had to use two cables for MFM and RLL drives because the 50 pin connector didn't have enough pins and those drives have an army of jumpers because every controller behaved differently. And despite of all this, the machines are still not natively hardware compatible with any other computer IBM made.
I remember seeing these massive floppy drives still being used at a CIBC bank in the mid 2000s. First computer I had in the 90s had a 5" drive and a 3". very cool
The OLIVETTI M3030 used two 8" Floppy Drives.
Freaking amazing! Kudos for you!
I was going to make some magnetic media jokes but it just goes over everyones’ heads.
Al Shugart also founded Seagate - who is still around and dominant today. They also created SASI - Shugart Associates Systems Interface - which was stadardized and became SCSI used by Apple, Sun and many Minicomputer and Mainframe suppliers. It took the workload of managing the drive off of the main system and turned it into a "block transfer" device. This greatly simplified the drivers AND allowed the peripheral to change to tape, RAID or whatever on its own with the host not having to spin up yet another driver. Seagate was also the first to introduce optical connects between peripherals. As SCSI got faster and wider the connector and cabling became unwieldy. In came the low power laser with cheap fiber to carry the load. The prices dropped so dramatically that it drove down fiber networking. Its why you can have cheap mega-datacenters today. If there isn't a Shugart Prize, there should be.
I wanted to also chime in - the floppy (flexible) media and format thereon was quite unique for different systems. Same physical "blank" could be soft sectored (one hole per revolution) that indicated the start of sector zero. For those you had to write the entire track. (Read/Modify/Write) Some were hard sectored - wherein every sector had its own hole and the hardware counted them to read/write the specific one. No need to read the whole track. Every company had its own track definition. An Apple disk had a different format then a Xerox or IBM. I think the most interesting variant was the Apple LISA floppy (remember Hard Drives (from Seagate) were just coming out when the LISA was introduced). The LISA floppy had two slots on oppsite sides. This allowed it to read in the first half of the rotation and write as the media spun around to the other half. No one else ever did this to my understanding as it made for a much more expensive drive but as the LISA was a virtual memory OS it was necessary. Hard drives changed it all of course. (A 5 MEGABYTE drive in 1983 cost $5000 and we wondered WHY anyone needed that much storage. Hell OS/2 followed by Windows NT shipped in a huge box with 56 floppies! ROM was hugely expensive until FLASH and even that was costly until the MP3 revolution and SmartPhones starting with the Qualcomm QPhone and Microsoft Windows CE Smartphone and Blackberry which predated all Apple by quite a while. )
This is the single most entertaining video I've watched on YT in years. As an old techie growing up 5.25FDDs, I'm so glad I found this channel!
Fascinating!
great episode!! i love the older complicated computer stuff .....brilliant job!
They don't make things like they used to - - and I am eternally thankful for that :) .
There's always such cool stuff on your channel. Things that I've wondered about in the back of my mind and often forgotten. Love these nostalgia trips and revisiting things. ❤❤
Computer archeology at its finest 😙👌
Thanks for shining some light on the 8 inch mysteries! I have gone through most of this myself too and got it roughly working on my PC - roughly because it seems not to be stable but maybe that is due to the media I am using, so thanks for pointing out the differences between the various media types.
Goodness me that win95 boot sound brings back some memories.
That sudden moment of nostalgia when you see disk format "BBC B"!
Fantastic love your team
Interesting exploration of the lowly floppy interface. I was messing around with some shugart drives on a true blue IBM PC 30 some years ago and encountered some of the same difficulties some I never overcame. More recently was working with some "newer" equipment running up against old problems that didn't just magically disappear with time concerning cable lengths and terminations.
Well yes, we all needed to know this! 😜👍💪💡
Ahh, this brings back memories. I spent most of my early career working on and with CDC equipment. The CDC floppy was the first soft media drive I ever worked with. I had to write some drivers for it back in the dark ages.
Excellent video as always Marc and crew. When I worked on those first PCs in detail it drove me crazy how many shortcuts and kludges were involved in "designing" the architecture. Signal lines repurposed. Triple fault to quickly move from 286 mode to real mode. Extended memory, Expanded Memory. . The kludges were like layers of an onion.
Cool, love the shout-out to Adrian Black. 😉
Seeing the Dolch all in one reminds me of my days in Q.93x E1 Primary Rate ISDN and T-1 telecommunications testing, we invested big money during the mid 90's. We had probably half dozen of those machines for Layer 2 and Layer 3 for pre regulation and compatibility testing, brings back many happy memories of worldwide travel and test labs. 🙂
I used to have Zenith 8086 PCs way back and the FDC on those had capability for all 4 floppy disks, in 5.25" and 3.5" (720k only). It required 5.25" drives with capability to handle DS0-3 for drives A to D. You could only use 3.5" drives as A or B unless you fiddled with the pinouts.
Try Greaseweazle, it is open source / open hardware magneric flux reader for FD. No need for fdd controler- it is USB.
I came here to mention that as well. It's a great way to hook any floppy to a modern machine and does a better job of reading data than a dedicated floppy controller ever could.
man, a Dolch PAC!!! you really have the best toys in business :D greetings from Brazil, Marc!
It was nice to watch. Thumb!
Best Cable Ever!
You folks may just have created the most authoritative 8" floppy drive video out there, thanks!
Check the digital basement channel (Adrian Black), he is doing a lot of 8" work lately as well.
"We're gonna bomb the enemy back to the Stone Age!"
"Geez Lieutenant, that's a bit harsh. I'm uncomfortable with bombing them back to the days of 8" floppy drives... those things were hell."
I remember the 9825 well... I grew up in the age of 5.25"... when I first saw the 9825, I thought (just like you say) "finally... grown up's floppies".
Sometime much later, in the 1990s I spent weeks trying to work out how to connect an old 8" drive to my PC.... If only I had had one of Antoine's little adaptor boards back then.
Great video. I Forgot about locking drive doors. But my eyes keeped locked at those 9 track tape drives under the table.
Now run it off an old disk washer. Kidding. No reason to waste your time doing something like that. Just keep restoring this stuff, it's the best!
Unexpected Adrian!
With this quality of sarcasm you could apply to be British. Love the Video.
Love the header :-)
After watching that I may need to go into "therapy" as it has brought back memories I would rather have had "buried".
Apparently, to create the 5 1/4" 1.2MB high-density floppy standard, IBM did the simple thing and basically took the 8" drive format and shrunk it. That's why the drivers are so compatible - the 5 1/4" HD format is literally the 8" format shrunken down. With a few more tracks since they halved the track width of the existing 5 1/4" format. That's why the number of tracks doubled, the use of 500kHz etc all came from the 8" format. It's also why there is the 360k/1.2MB floppy incompatibility. Note that there is also the speed difference - the 8" drive ran at I think 360RPM, while the 5 1/4" ran at 300RPM, which let you squeeze more bits in.
The 5-¼ also runs at 360 rpm when it is in 1.2MB high density (controlled by the density pin I talk about in the video). So, you got it quite right, except for the 3 extra cylinders, it’s a pure shrink of the IBM 8” format.
I never used 8" floppies, but I do recall an old Burroughs computer used for payroll in the institution where I worked that had them. Cool video.
Yes, our company would allow people to send in payments on 8" floppies. We had a cool automated reader that could read in a stack of them at once.
I appreciated the quick excerpt into playing the original Donkey Kong haha. Also, very interesting to see how much more mechanical devices were compared to now. I guess we can attribute that decreases to solid state? That might be a stretch because there are probably numerous things that contributed to that reduction in mechanical components and miniaturization.
Would be interesting if you can do a video on floppy-drive-interface tape drives some time. Info on how those worked seems to be some of the rarer info on floppy drive connections.
That Win98 startup sound at the end literally killed me.
Re: Capacity I used an Intel MDS development system around 1980-81 (for 8085 based product) with two FD-drives and am pretty sure the 8" FDs held 180kbyte SS and 360 kbyte DS ( I think the OS was CP/M or something very like it)
I remember the first version of the Burroughs B 2900 mainframe used an 8" floppy inside the cabinet to load the microcode. After a couple of years it was reengineered to use 5.25" floppies, like all the rest of the world by that time. The firmware was created on Convergent Technologies (later bought by Burroughs) B20 systems. They had a disk format all their own.
Microcode is the final frontier for retro computing enthusiasts... and mainframes themselves
Well, having tinkered with this a few years ago, yep. The basic operation didn't change. Mostly the interface, though the key signals are the same. The actual sector formatting was totally different.The 26-sector disk you used is the single-sided, single-density CP/M format. Also note that a few of the later PC floppy controller chips no longer handed single-density, or FM recording. If you really want to get into it, try running 22DISK (you can find it...) as it can format, read and write to the CP/M format. DOS and Windows cannot, nor can LINUX. A variant used with double-sided, double-density 8" used 8, 1024-byte sectors. I have built my own adapters, even designed one to do the automatic reduced write current for the inner tracks > 40. Later 8", and all the 80-track PC drives did that automatically in the drive itself. Most of the single-sided 8" did NOT have that, though only a problem when writing or formatting. I personally have several 8" drives, recently refurbished a huge Siemens FDD-200-8, 8", double-sided. Next is to get a PerSCI 299 DOUBLE - 8', double-sided drive going. It had TWO 8" 'drives' in one full-height 8" size. THIS one is extremely RARE to find! The original Shugart 50-pin interface allowed the selection of FOUR drives per interface, this was reduced to only 2 with the 34-pin PC interface, and the dreaded 'twist' was to eliminate the need to manually set the drive ID. (Most drives came pre-jumper-selected for DS1. (Also, the motor-on signal as well.) I have been able to access 8" drives in LINUX as well through the PC floppy port...
2:40 - On the top right you can see the venerable HC-.003/U crystal package!
(Yes, I know it's a capacitor, I was just amused at the similarity of shape, and the novelty of a huge motor start cap on a storage device :D )
I used to work for 3M Camarillo. We made floppies.
The door lock was a requirement as the old heads where little coils mounted on a springy metal square. Any force sidways would have them destroyed by beding them. And pulling a disk while the heads where lowered would have don that when running the cover cut-out into the heads. Later the mechanics where coupled so the heads where lifted when the door openeer was used. Then they found a way to avoid the springy head carriage and just pot them in some acrylic like stuff that was also manufactured in a rounded shape. So the edge of the cut out for the magnetic disk would just slide over the head without damaging anything. That resulted in even more simpler mechanics as the lower had wasn't to be lifted in any way at all anymore.
17:04 Straps! That's the origin of "strapping" as a synonym for configuration. "Is it strapped right?"
Interesting that this got uploaded right as I started thinking about a 8" drive subsystem i'm gonna be building for my Altair 8800c down the line! I'm using a FDC+ so I have the luxury of just being able to use soft-sectored drives. (Whew)
I love portables, I want to collect them all.
One of the problems with the 8 inch disks, is some of them did not have a felt liner inside the jacket to lubricate the Mylar disk. So when the Mylar disk bound up inside the jacket, the drive motor would literally turn the disk into confetti!
i remember the 8" floppies.... crazy how tech changed
o0O (The sarcasm is strong with this one) ... but warranted
Never saw 8" floppy stuff in real but looks like a lot of fun!☻
Ah yes, at 26:55 that's a Tandberg drive. I worked on many of those when I worked at CPT, they had a tendency to go out of alignment often due to how the seek motor was mounted. I cursed them often (I did lots of realignments in the day...). But I also worked on many of the CDC drives as well a they were used in the Vydec dedicated word processors. Fun times...
I used NEC H03's with dual 8" drives. Circa 1980's
I have always wondered about the wire twist :)
great job :) i still have a one brand new box of 8" disks :)
The very first IBM PC I got my hands on had 180kB single-sided 5.25 floppies... the first thing users did was to upgrade to the 360kB DSSD drives. Somewhere in my junk I have both of those old SS drives... was going to make a floppy for my RatShak Model 1 and never got 'round to it. Of course, the *very* first PC's were cassette-based, just like my Model 1. Long live EDTASM!
Cool, never heard of "Champ Kong" :)
There were also “hard sector” drives with an index hole for each sector, not just once per revolution. The Pertec drives on the original Altair 8800 were that way.
I used to align floppies in the 80’s - you always put disks into drives when they were powered up because most of them would spin the motor as you inserted the disk which massively helped centre the disk as you close the door. I would never put a disk into a powered off drive