I ran into so many issues while testing these MFM hard drives

#autopsy #retronoises
Time for some more MFM drive testing. Whenever I end up with these drives, testing them if always a bit of a pain, but I never expected all the issues I would run into testing these drives. So enjoy the struggle I went through testing these relics of the past!
-- Info
Drive 1 - Fujitsu Limited M2227D
Drive 2 - Computer Memories Inc. CM 6640
Drive 3 - Magnetic Peripherals 94205-51 - Control Data Corp.
Drive 4 - Magnetic Peripherals 94155-86 - Control Data Corp.
Controller 1 - Western Digital ST-506 WD1002-WAH
Controller 2 - Western Digital ST-506 WD1003-WAH
Programs used:
- SpeedStore
- SpinWrite II by Steve Gibson
-- Video Links
Thompson Toolkit:
www.tasoft.com/toolkit.html
Thompson Toolkit v1.5:
archive.org/details/thompson-...
Thompson Toolkit v2.0:
archive.org/details/thompson-...
Adrian's Digital Basement Merch store:
my-store-c82bd2-2.creator-spr...
Support the channel on Patreon:
/ adriansdigitalbasement
Adrian's Digital Basement (Main Channel)
/ @adriansdigitalbasement
-- Tools
Deoxit D5:
amzn.to/2VvOKy1
store.caig.com/s.nl/it.A/id.16...
O-Ring Pick Set: (I use these to lift chips off boards)
amzn.to/3a9x54J
Elenco Electronics LP-560 Logic Probe:
amzn.to/2VrT5lW
Hakko FR301 Desoldering Iron:
amzn.to/2ye6xC0
Rigol DS1054Z Four Channel Oscilloscope:
www.rigolna.com/products/digi...
Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:
amzn.to/3adRbuy
TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)
amzn.to/2wG4tlP
www.aliexpress.com/item/33000...
TS100 Soldering Iron:
amzn.to/2K36dJ5
www.ebay.com/itm/TS100-65W-MI...
EEVBlog 121GW Multimeter:
www.eevblog.com/product/121gw/
DSLogic Basic Logic Analyzer:
amzn.to/2RDSDQw
www.ebay.com/itm/USB-Logic-DS...
Magnetic Screw Holder:
amzn.to/3b8LOhG
www.harborfreight.com/4-inch-...
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
www.ebay.com/itm/14-16-18-20-...
RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
www.retrotink.com/
Plato (Clone) Side Cutters: (order five)
www.ebay.com/itm/1-2-5-10PCS-...
Heat Sinks:
www.aliexpress.com/item/32537...
Little squeezy bottles: (available elsewhere too)
amzn.to/3b8LOOI
--- Links
My GitHub repository:
github.com/misterblack1?tab=r...
Commodore Computer Club / Vancouver, WA - Portland, OR - PDX Commodore Users Group
www.commodorecomputerclub.com/
--- Instructional videos
My video on damage-free chip removal:
• How to remove chips wi...
--- Music
Intro music and other tracks by:
Nathan Divino
@itsnathandivino

[@tarzankom]

Being over 40 years old myself, I can totally understand why 40 year old HDDs are tired and broken.

[@tcaldwe]

Amen brother. Us disco children are getting long in the tooth

[@senilyDeluxe]

The moving parts degrade - ours just like the old HDD's. Worse - the RAM in my brain must've been manufactured by Micron Technologies... (I'm almost 39, so I've been made in the time period when MT started making their infamous senile RAM chips).

[@dennisp.2147]

Wait until your 50's...

[@angrydove4067]

Wait till you hit another 20 years.

[@hessex1899]

A quick recap and some deoxit will sort that right out.

[@_derSammler]

As for the track 0 issue in DOS: if the error is on head 7, just reduce the number of heads in the BIOS so that head 7 is not used. (maybe also explains why it was used as 30 mb previously already, since less heads means less capacity)

[@AndyHullMcPenguin]

I can verify that this does work with some drives, but you do obviously loose a whole platters worth of capacity, assuming there is not some more trickery going on in the firmware of the drive that spoofs the number of heads and sectors. Some dives report multiple heads eight, twelve, or whatever even though there are actually only two or four.

[@nickwallette6201]

If the problem is format, scoot the partition up by one track. Or just use a more flexible format tool that is more flexible with reserved sectors.

[@Inject0r]

Would it also be possible to lower the amount of sectors? I don’t know if it’s counting from the first sector or the last sector? ¯\_(ツ)_/¯

[@MonochromeWench]

@@nickwallette6201Yeah manually setting the partition parameters and setting the starting sector to 1 or higher should be enough as it is the format command that is failing.

[@donkeymedic]

The problem is not being able to format the drive, It's about being able to boot from it. If I remember, some older drives however, can have a track adjustment. Sometimes known as track zero sensor or offset. This can be a pot or screw that physically adjust the track alignment. Has the drives progressed to IDE, this was done in firmware or internally.

[@vwestlife]

Andy was probably using DOS 3.x which only supported a maximum partition size of 32 MB, so rather than split up a 40 MB drive into two partitions, he elected to leave some of it unused.

[@pickoftheglitter]

Maybe you're right.... but back in the days it was a really weird behavior, since 8 Mb was a lot of space, so you would try to make two partitions instead of leave 8 Mb unused (I say: eight megabytes! eight precious megabytes! LOL) But of course maybe Andy was just a collector that formatted that thing in the 2020s and he didn't care about 8 Mb of space...

[@TheErador]

Businesses may not have cared that much it's just more to look after, easier to support a homogeneous environment

[@Stoney3K]

The system appeared to be a clone of some kind of master system that it was copied from. It's possible that the original master system had a 30MB drive, which they couldn't source anymore in newer machines, so the drive geometry was just set to match the original system so it would be the same from the software's POV.

[@Blackadder75]

@@pickoftheglitter 8mb, that was enough for KQ5! (or a whole bunch of earlier EGA Sierra games ) Andy and his stock market can go elsewhere

[@AureliusR]

no, it's way more likely that they avoided using the bad sector on head 7 by configuring the BIOS to 6 heads. Nobody would just throw away 8MB for no reason.

[@Vans_Garage]

I had a similar track 0 problem back in the day. I used CP/M 86 to create a small partition (

[@raven4k998]

can one get the magnetic medium restored on an old drive like that?

[@SonicBoone56]

Gotta love how old MFM hard drives sound like old mechanical tornado sirens.

[@diskettenfett3161]

On stepper hard drives, you can often get rid of bad sectors by slightly moving/rotating the stepper motor so the tracks will end up in a slightly different position. Moving the track 0 sensor in or out a bit might also help, but will only work in increments of a whole track. A complete low level reformat will be necessary after fiddling with the track positions. I have revived many stepper drives this way.

[@raven4k998]

is the warranty still void if removed?🤔

[@GarthBeagle]

Love these HDD investigation videos!

[@granitepenguin]

PC-NFS is a DOS version of the NFS protocol for accessing network shared volumes that was the de-facto way to share files over the network in UNIX (think the UNIX version of SMB). I still use NFS all the time on Linux for work. Considering all the other UNIX tools that are on this system, they were probably used to using NFS. I'll bet they were using this system to talk to UNIX systems over the network.

[@PaulaXism]

I thought the same thing. Why do people these days immediately assume directories with any name related to "stock" are financial casino stuff when the most likely use Andy had was warehouse stock control. I think it's a factory warehouse management machine because there were other entries like "store" and "gin" "gout" etc.. This all rings bells with me because at a time long long ago I worked in the stock control side of a large paint manufacturer.

[@granitepenguin]

my first PC clone was an Amstrad PC-1512 with dual floppies in 1986-ish. I remember talking my mom into getting a 40MB MFM drive installed for $400. My argument was "it's so big, we'll never fill it." We never did :-)

[@andygozzo72]

a half height type (same size as the floppy drives) 'should' fit, the problem then is the controller and the current taken by the drive and controller board...

[@russellbrown1138]

Same Here PC1512DD with 1/2 Height MFM 20Mb drive, 8087 CoPro and V30 Chip, 2Mb expanded memory board. Ran Autocad in CGA mode just fine along with many, many Sierra games back in the day.

[@ruthlessadmin]

This video made me very thankful that I'm not old enough to have ever dealt with MFM. I first started building PCs when I was 10, in about 1993, well after IDE had taken over. That BrainMaker software seems to have a website...

[@Blackadder75]

I am a few years older and I am sure our first family PC, also a 286, had these kind of 40ish Mb drives. and since I became the wizkid in our family pretty soon, I must have dealt with this heads and cylinders stuff a lot, but I don;t remember the transformation into IDE drives anymore, our next PC was a 486, but I forgot what drives it had.

[@argvminusone]

When I was a kid, the first computer my family had, had AMIBIOS just like this, and an IDE HDD. As I recall, the BIOS had a menu option to auto-detect connected hard drives, and it was a mystery to me why the BIOS would let you enter the cylinder/head/sector size of the drive when it could get that information from the drive itself. Only now did I learn that this was because that BIOS is also compatible with ST506-like drives that, unlike IDE drives, can't report their own size like that. Next mystery: why Western Digital decided to create IDE instead of just using SCSI. The ST506 and its controller interface were Shugart products, and people wanted drives to have built-in controllers instead, so Shugart also designed an interface for such drives: SASI/SCSI. That was several years before IDE was developed, and got traction in various other computer ecosystems (like Amiga and Macintosh), but in the IBM PC ecosystem, Western Digital came up with IDE instead, and that's what caught on. I wonder why. Were there perhaps SCSI license fees that they wanted to avoid?

[@Ktithra]

As another option, in DOS utility "Debug" enter g=c800:5 to enter the hardware low-level formatting utility in the controller. (In case you weren't already aware.)

[@stefanhennig]

I can't find the word to describe how glad I am that I don't have to deal with this anymore. Brings back so many memories, none of them good. We have come a long way since this.

[@erinwiebe7026]

I use vim daily, but I don't think I've ever seen vi in DOS before. I'll have to look that up!

[@adriansdigitalbasement2]

It's really old and tiny -- I have not idea where I found it but it works on the oldest versions of DOS on systems with as little as 128k of RAM.

[@ChristopherHailey]

I used to use a version vi for does back in the day, I don't remember who made it. I also ported a lot of the Unix utilities to DOS, stuff like cat and awk and sed, and even Lex and Yacc to work.

[@ChristopherHailey]

I can relate to this, I put an unknown Seagate ST-225 drive in a Unix machine from the '80s and it literally took days just to get all the bad blocks flagged. When I finally got the OS installed and booted it was quite a thrill!

[@hattree]

On that screeching hard disk, I can remember having a full height drive with a static remover on the bottom of the bearing that would chatter like that when spinning. We just put a little dielectric grease on it.

[@EShirako]

That could make sense. I was also wondering if a head was having a too-close-encounter with the medium, but that's usually a very consistent sound, or at least only changes when you move the heads to seek data to the 'troubled area of media' or whatever. Amazingly, of all the things I DO already know from working on computers from this era, that's NOT a problem I have ever come across before. That's rare for me to have happen...learn something new every day, even about retro-stuff! :)

[@garthhowe297]

My first hard drive was a 10MB MFM drive, and it was $500 CDN, as I recall. I was so excited to get such a large and blazing fast drive.

[@scottlarson1548]

I definitely remember setting up a quasi-Unix environment on my first DOS machine at home since I used nothing but Unix at work. It had a standard Bourne shell and dozens of Unix command that were DOS ports of the originals. I could fool myself into thinking I was on a genuine Unix machine as long as I didn't try to put processes in the background which of course was not possible.

[@kaitlyn__L]

That's so cool. That's what I expected it was, just a port of sh and other utils, but dang if it wasn't effective at getting that feel. Even just watching it being used seemed almost like a different system.

[@argvminusone]

DJGPP? I believe that was the standard way to run Unix programs on MS-DOS. At about the same time, free and open source Unix-derived and Unix-like operating systems for 386 PCs also started appearing, like 386BSD and Minix.

[@scottlarson1548]

@@argvminusone It may have been produced by DJGPP but like I said it was just a bunch of Unix programs ported to DOS. You could even run them from the DOS prompt.

[@rayoflight62]

What gave me lot of troubles with MFM and RLL 5¼ hard disk drives (1987 to 1989), was the wrong disk geometry. The MFM drives don't work if you don't input the correct geometry into the BIOS and the format coincides. You need to do a Low Level Format (the utility is usually in the BIOS) with the correct numbers of CYL, SECT, HEAD etc., otherwise the DOS Format - the high Level one - won't find the track 0. In addition to that, the controller must support the geometry and its BIOs must talk with MoBo BIOS - not a problem if you use the original controller which was with the drive...

[@arnlol]

You can get the Fujitsu working easily, since you already use speedstor, you can use it to make partitions specifying the cylinders to use, so make the partition start on cylinder 1 and it will work. (You could also set it as 6 heads and sacrifice the last 2 and that would work as well but loosing a lot of capacity). Seems like the CDC/Imprimis drives (the black ones) certainly are quite reliable compared to other drives of the time

[@raven4k998]

loose parts or screws loose inside the hard drive?🤔

[@psxemulator]

I noticed SNASM658 @ 45:20 which was a Super Nintendo 65816 assembler made by Cross Products in the UK used by various game developers back in the day (we used to use it).

[@monchiabbad]

MFM is a format method that the controller used. You can format most if not all with an RLL controller to get 30 to 50% more capacity out of a ST-506 or ST-412 interfaced HDD. You should try it with all of these HDDs. All you would need to do it re low level+format the hdd on the RLL controller.

[@eDoc2020]

The capacity gain is almost always 52.9% because you go from 17 to 26 sectors per track. But it really does require a better hard drive. @themaritimegirl tried canging from an MFM controller to an RLL one and the resulting setup had an ton of bad and unstable sectors, compared to zero on MFM. If I recall correctly RLL requires about 20-30% additional physical bandwidth. Older high capacity drives are probably least likely to work but drives at the tail end of the MFM era are more likely to work.

[@JohnGotts]

Citation? Back in the 1980's-1990's I never encountered an MFM drive that did not work perfectly fine with an RLL controller, nor have I ever read this or heard this anywhere during that period. I have only read your KZbin comment, and maybe an offhanded comment from an old Adrian video about supposedly less reliability from RLL. I do not believe any of this to be true. I formatted over a dozen different drives from all sizes and eras and RLL never had reduced reliability compared to MFM. As far as I'm concerned, all working MFM drives will have equal reliability formatted as RLL unless I see evidence to the contrary. At this point these are old drives, but I do not believe that would make RLL marginal and MFM work fine. Conclusion, using MFM is wasting your money and sacrificing space for no reason.

[@JohnGotts]

But it is possible to have a bad or dodgy RLL controller. I was only using reliable hardware at the time of my testing.

[@eDoc2020]

@@JohnGotts As I mentioned earlier @themaritimegirl here on YT did some tests with a Kyrocera drive. It's possible her controller was dodgy but AFAIK they're mostly digital so this is unlikely. If the controller was dodgy I would expect the errors to appear randomly but instead they were focused on certain areas of the drive.

[@eDoc2020]

@@JohnGotts For the opinions of somebody who was actually in the industry, there's somebody who operated a store called Red Hill Technology. I'm not going to try to link here but you can do a search on "red hill mfm rll" without the quotes and I'm sure you'll find it.

[@LucidSystems]

I'd love a Playlist of just the videos where you explore the files on old hard drives.

[@rdh2059]

I remember using my MFM hard drives. My brother and I ran a BBS back in the day with them and had to take a day every 6 months and spend it reformatting each of the BBS hard drives. We used ERLL controllers which doubled the size of each MFM hard drive. Between the error scanning, FDISK and the normal dos Format command, it was usually an all day event...

[@AndyHullMcPenguin]

Reminds me of similar time scales installing drives in Altos Xenix machines back in the day. It was not unusual to spend an entire day or more replacing, formatting and restoring a 20Mb multi-user accounting system. Bear in mind that while I was working hard to get it restored, most of the accounting staff (in some cases thirty or so well paid individuals) were sitting around shooting the breeze as they were basically dead in the water until the system was back up and running. Every so often a "higher up" would ask, "No pressure, but have you any idea how long this is going to take?" The down time was costing them a fortune. "Any chance of getting a cup of tea?" was one of the many polite ways of telling them to piss off as it will take as long as it takes. I'm currently backing up a virtual machine in a rack in my office at a rate well in excess of 20Mb per second. Quite a contrast.

[@retrozmachine1189]

@@AndyHullMcPenguin A real estate agent in my town had a Altos that we would work on, it was a 286. Pretty vague memories of it really, serial card for the terminals, file system card, 512k of RAM (that doesn't sound right to be honest but 512Mb would have been ludicrously expensive).

[@AndyHullMcPenguin]

@@retrozmachine1189 Sounds like a 2086 here is a picture of one -> i.pinimg.com/originals/c2/ae/95/c2ae951bc321323ab0cfe2b6178eb01d.jpg There was a range of similar "super mini" computers, a 1086,2086,3086,3068 and a number of different form factors with a 486,586,686,580, the 1000 series and a number of others. They were pretty pricey too back in the day.

[@thisnthat3530]

MFM HDD manufacturers would turn down the write current when testing the media for the printed defect table. The idea was to provide a margin of error for normal operations. I used to ignore the list and just let DOS mark sectors that were bad at 100% write levels. I never lost any data because of it. Adding the track to the defect table would mark all 17 sectors as bad, but DOS would only mark a single cluster which was a smaller amount of lost space.

[@hamlett22me]

I've been using a 1.05GB Seagate Hawk 50 pin SCSI hard-disk as my C drive with an Adaptec AHA-1542CP SCSI controller in my IBM 5170 for a decade now. That hard drive was manufactured in 1993. Perfect. No data loss of any kind. Yes, MFMs were goofy with data over time. Love my SCSI drive in my 5170. Great video. Thanks for sharing all that work.

[@seansretroverse9082]

"It's a UNIX system! I know this!"

[@JamesPotts]

Those unix utils are probably MKS or Thompson. I don't remember enough to recognize which.

[@tcpbox]

Adrian thank you for this videos, it makes me remind a lot things from my beginning with pc-xt and pc-386 I had very good times.

[@tomekrv942]

Great video. I like these old drives and want to see more.

[@MicrophonicFool]

It might be they formatted for 30MB as I think DOS 3.1 and before would not recognize more than 32MB initially. With BIOS additions this limitation was solved. The only thingwhich eventually solved was LBA and an *almost* vitual head and cylinder situation, ALL as Type 17 or 20/21 Winchester spec for compatability

[@nickblackburn1903]

This was fascinating thank you Adrian.

[@ForgottenMachines]

47:44...wow...the awesomeness just keeps coming. Not only do I LOVE your videos, I LOVE your videos most about vintage floppy and hard drives of ALL kinds...and to top it off, here's another Tshirt sighting...wow, thanks!!!!

[@ronsingh]

Man, it was fun seeing you go down this memory lane with MFM, I spent many years dealing with these drives back in the 80s with my fav probably being the Miniscribe 3425 as it rarely died. Thanks for the deep dive.

[@CRSolarice]

I remember Laplink and used to use it before I installed networking cards and Lantasti. (Btw Xtgold is an awesome file manager and I consider it to be the best that there was for DOS....). 31:21 I have the thought that PC-NFS is a Util for PC that enables access to Data and Applications that are located on Unix, VMS and/or Mainframe based systems. Also may provide Unix printing and telnet support (Sun Micro, Enterprise based)...

[@GodmanchesterGoblin]

If you're a Windows user then there is still ZTreeWin which is a very good enhanced version based upon the Xtree / Xtree Gold utility. I still use it under Windows 10 since it can do stuff that most Windows utilities can't

[@williamogilvie6909]

A friend of mine, in 1992, got a box full of hard drive cards, surplus'd from a school district. He tried to rope me into helping him evaluate them so he would be able to resell them. I tried to disabuse him of that notion, without success. This video eminds me of that episode. Free junk will always be junk. There used to be a warehouse in Sunnyvale, called Wierd Stuff, that sold old computer gear, cables, you-name-it. They had HUNDREDS of MFM drives. Not a fast mover, even 10 years ago. I bought lots of MFM drives in the '80s. In 1988 I helped bring an RLL drive to market. RLL drives used a different encoding method that resulted in more predictable sector lengths, hence more capacity and shorter seek times.

[@terryc7142]

I remember when IDE first appeared on the scene. Made things much simpler when building systems! The old RLL and MFM drives were a bit trickier.

[@argvminusone]

You still had to get the jumpers right for primary/secondary drive, though, since each IDE bus could hold two drives and they couldn't sense their own position on the bus. That wasn't fun. Nowadays, most “buses” (PCIe, SATA, USB) are actually point-to-point serial connections that always have exactly two devices on them (one on each end of the “bus”), so there's none of that jumper stuff any more. That requires extra electronics that would've been prohibitively expensive in the 1980s and 1990s, but decades of tech improvements have reduced the cost to basically nothing, so now we can get away with it. Good thing, too, because serial is much _much_ faster.

[@dillonblue4555]

Qedit was great. It had the feature of being able to cut and paste columns in a document. If memory serves, it could also read unix text files without proper cr/lf and save it to the pc, so the file would be useable. Also I remember using PC-NFS as a TCP-IP stack and Qedit would be really handy dealing with text files straight off a Unix NFS mount point.

[@TheBlueCoyote]

When the drives spin up, they sure sound like a model jet preparing for takeoff

[@kaitlyn__L]

That person took a lot of care to customise their UI. All the colours for the different files, all the shell scripts, gosh. I love that Thompson Utilities thing especially, how cool and weird! I have to look-into whether that's an actual *nix that somehow cohabits with DOS, or if it's (more likely imo) just "sh" and a few other BSD/GNU utils.

[@ricardog2165]

There's a similar open source Unix environment for Windows called Cygwin.

[@GavinR824]

QEdit got me through years of writing in my university courses. One of the best plain text editors for DOS.

[@tinfoilcat]

ypclient - probably for talking to Suns YP (later NIS) directory service. If they used it. Cool find, always nice to see old production/power user machines instead of ye olde plain DOS + Norton + WP. :)

[@brianhginc.2140]

@18:33, that was my first HD on my Amiga 1000 with a home made 68k buss adapter to a PC style AT controller. Not the fastest thing or auto-booting like a true Amiga HD controller, but it was dirt cheap and functional. (When I say cheap, I mean 175$ for everything VS something like >1k$ for an Amiga 1000 HD back in 1988).

[@JSMCPN]

Always good to have a copy of Spinrite handy

[@badmonkey0001]

I haven't heard the name "Thompson Toolkit" in a very very long time. Amazingly, Thompson Automation Software still has a website online and a page describing Toolkit, but they no longer offer it for sale or download. Glad you managed to nab a copy!

[@rabidbigdog]

Many of us oldies used to add a few *nix commands to dos and create dos commands for *nix to stop the frustration of typing 'ls' in dos and 'dir' in *nix.

[@Zhuge_Liang]

I'm adding my vote for "preserve this stuff." I can't ID all the software on there, but netstat is network testing stuff, and on the whole, that's the oddest and probably most interesting combination of software I've seen on an MFM hard disk. It may need "de-identifying" as scrawled upon the Technician's Creed, but that is an astonishing treasure trove otherwise. EDIT: Sounds like you low-levelled it... sadboi. And, it quit working. Thompson Utilities should be fun to hunt for info about.

[@adriansdigitalbasement2]

I did preserve stuff from the drive I erased - it was difficult to get the stuff off the drive because of disk manager so I didn’t include any of that in the video due to length.

[@Zhuge_Liang]

@@adriansdigitalbasement2 Fantastic news! Thank you!

[@adriansdigitalbasement2]

archive.org/details/thompson-toolkit-v-1.5

[@adriansdigitalbasement2]

archive.org/details/thompson-toolkit-v-2.0

[@ESDI80]

That's funny on the 20MHz ISA clock. Those older WD controllers are picky about speed and tend to have issues in higher speed 286s and newer. No surprise the CMI drive was bad. Those were problematic on a good day. The CDC drive is an excellent performer as I have a few of those kicking around and they are solid. I also love the sound of them. I have a couple 5 1/4" full height Fujitsu drives and they work great as well.

[@HeffeJeffe78]

A lot of those utilities in the \BIN directory were commonly found on BBS systems in the very early 90s

[@jjock3239]

The innards of those hard drives are so beautiful. I have a bunch of old drives, and am going to pull the disks and make a mobile.

[@stevesether]

Watching this makes me think how ancient these hard drives looked to me in about circa 1994. I had an Amiga back then, and there was a local surplus store called Ax-Man that this gigantic MFM drives for nothing. I'm not sure what capacity they were.... maybe 10 MB or 20? But even back then, looking back just 7 or 8 years these drives seemed like something out of the stone age compared to my "modern" 105MB SCSI drive that was so much smaller. I never had PC during this era, so these beasts just looked like something from another world, not unlike they do now. Yes, the capacities are much much larger now than my 105MB drive, but the technology is still basically the same, and SCSI still exists of course, and you can still buy SCSI controllers that aren't too old that still support that 40 pin standard.

[@ed731pdh]

Run Length Logic (RLL) cards were supposed to be a method of being more efficient in data storage, often increasing the MFM drive capacity by a third. Unfortunately RLL long term proved to be unreliable in operation, which was a shame as it was often cheaper to have a smaller drive plus RLL controller to get the size you wanted.

[@rah975]

RLL (Limited, not logic) as a format lasted well into the SCSI and IDE eras, when PRML took over in the mid 90's. The reputation for reliability problems with RLL was caused by converting MFM drives that weren't quite able to keep up with the data streaming from the media. (BTW, MFM is a type of RLL encoding)

[@cacheman]

31:40 QEdit was my main editor for years on DOS. IIRC it could be configured to operate very similarly to the Borland IDE editor w.r.t basic movement and copy'n'paste, so it fit like a glove. It's where I picked up a habit I still have today, which is that of using a 'cursorline' (in VIM parlance, it's a highlighting of the line the cursor is on).

[@ricardog2165]

Ah another QEdit user. It was what I put on my standard "Tools" floppy and was also my favorite. I also used a demo version of MultiEdit that worked with a mouse.

[@steveshah5059]

The Qedit commands were based on WordStar, so not surprising WordStar4 was on the system. Borland used it for their IDEs on the Turbo editors as well. Qedit was awesome because it was insanely fast and memory efficient so you could load large files for editing. If memory serves correct, it the binary was < 50k so you could load text files that were upwards of 600k (with EMS setup). Qedit was the only editor I ever ran across that handled some of the stranger character modes of VGA like 132x43 which felt like a obscene amount of screen real estate when you're used to 80x25. :-) The e3 editor on Linux followed in the spirit of Qedit being written in assembly, very lightweight, and Wordstar command set. This made e3 great for floppy recovery disks and PC based embedded systems that used small flash drives.

[@peebola]

I used it too, and still sometimes use its windows successor, the semware editor. The macro recorder was a fantastic tool for editing text files.

[@Choralone422]

I watched this video last night and reflecting on it today I just had to comment and say I was so glad I got into PC's in the early 90's when IDE hard drives were basically the standard. I saw a couple of MFM/RLL drives back then so these types of videos are always interesting for me! Even with some of quirks of early IDE drives like the BIOS size issues, PIO modes and later DMA issues they still seem a lot easier to deal with than MFM drives.

[@adriansdigitalbasement2]

IDE just made everything so much easier. It eliminated so much frustration and when we moved to these drives when I worked repairing machines, I was so damn excited too. Even now these drives are such a pain.

[@electrohoard]

I ALWAYS prefer to keep my vintage electronics and mechanical devices as original as possible, but I have given up on MFM drives and now just use solid state. Even those that still work will very soon fail, so I have finally accepted this fact and moved on… Thank you for the video Adrian!

[@robertchapman6250]

I believe the drive you took apart would have worked if you would have let it warm up. By the sound of the drive spinning up, it was not quite getting up to speed. The barrings take a little time to warm up and thin out the lubricant. Eventually the drive would get up to speed and the heads would unlock and start seeking. I have had this happen a few times on old drives that have been sitting around for many years. Several drives I have worked on in the past, seemed like they were not working, and after about 10 minutes of spinning, the heads would suddenly unlock and the drive would start working. Good effort on saving old hardware, love the show.

[@8BitNaptime]

QEdit! It was amazing!

[@hattree]

Thompson Toolkit is for programming Unix on a PC with DOS.

[@Chris_In_Texas]

4:30 "High speed" drive and MFM in the same sentence.... 😁🤣 Its just about the same as my Micron 9400 U.2 drive array.. 😲👍

[@_irdc]

About the bad sector on track 0: since sector 0, where the MBR and thus the partition table is located, is still fine, it should technically be possible to specify a partition layout which completely skips the entire first track. Not in DOS' fdisk, but maybe in other software? I know Norton Disk Edit contains an advanced partition table editor (Object -> Sector 0 and then View -> as Partition Table).

[@docnele]

He can try LL format to lower capacity (by disk geometry), so that bad sector might get skipped.

[@_irdc]

​@@docnele Now I'm thinking this was how it was initially formatted for 30MB: by specifying 6 heads instead of 8.

[@retrohaxblog]

Heh, sometimes I think we are all connected at some weird level. I was working on MFM drives for the past few days and now this video surfaced... :D btw. Awesome video as usual :D

[@granitepenguin]

This is the real quantum computing that's happening today ;-)

[@solarbirdyz]

There was a DOS utility that would rewrite, on a per-sector basis, the low-level AND high-level formatting on a per-sector basis, thus allowing you to effectively refresh the write age of your drive. You'd actually see performance improvements after running it if you had an older, longer-time-formatted HD. I don't re member the name of it at all, but we used it in the lab every six months or so. Probably more than needed, but, well. ETA: It wasn't Spinrite, but it did the same sorts of things.

[@chadhartsees]

I always wonder when we see something unusual if it was more engineers finding a new way to do something or just having to purposely work around some patent they didn't or couldn't license.

[@const_cast]

I have the same full-height CDC 70MB drive, and mine has the same weird intermittent bearing noise. It also works perfectly.

[@PaulSleigh]

I remember QEdit! It was an excellent text editor, well ahead of its time. It was renamed/sold and still exists under the new name of TSE (The Semware Editor). I remember its macro recording/replay/editing feature made my software development life much easier for many years. Also, Brainmaker was, if I remember correctly, some kind of intelligent tree-structure information tool, hyped beyond all sanity in the 1980s and then never seen again. I remember a breathless article about it in Australian Personal Computer magazine years ago.

[@jeromethiel4323]

MFM, short for Mother Effing Medium. ^-^ These early hard drives were plagued with issues, mainly manufacturing tolerances and control schemes jut weren't good enough yet. But we had to go through these crappy early drives to get to the truly great ones we have today.

[@ManuelSchulte007]

Terrific video, very interesting! Thanks. For the mfm drive that could not format under DOS because of the faulty sector on track 0 you might want to format it under Linux or something... That might well work... 😁

[@dawnmitchell8213]

I can’t believe how much computer knowledge has vacated my brain due to its obsolescence.

[@booboo699254]

That CMI... they were the worse drives from memory. Too bad it's lost here, but they weren't great when new.

[@the_kombinator]

I had a 286 somewhat recently which had the autodetect feature and it worked with MFM drives.

[@keithrosenberg5486]

I remember having to low level format the MFM drives. Quite a pain.

[@fattomandeibu]

My A1200's HD makes the same noise as that working drive, and I've been using it for about 2 years without issue. It originally didn't work well, not broken, but sometimes it could take a while to read/write data, but the longer it was powered on, the better it got to where it pretty much works like it originally did. If it weren't for the noise you wouldn't even realise it was "bad". Of course, that's a 2.5" IDE drive, but it's the exact same noise.

[@JenniferinIllinois]

That drive starting up around 19 minites sounded like it was crying. 🤣

[@AndyHullMcPenguin]

For a drive that has bad sectors on track zero, one trick that sometimes works, is to move the track zero sensor slightly to reposition the area the heads will seek to for track zero. It also assumes you have access to to the sensor and/or the "flag". If you move it in or out by a fraction of an inch, you may find that the bad sector goes away, or moves to track 1. This assumes a number of things. A) You have access to the sensor or the flag on the end of the head spindle. Often the spindle flag is held in place with a screw and some screw lock compound. Sometimes the optical sensor screw is accessible on the PCB or the optical sensor can be shifted by melting the solder and tweaking it slightly. B) You can do a low level format with a tool that will write the tracks from scratch in whatever position the track zero sensor winds up in. C) The bad area doesn't cover the new track zero also D) The drive is happy to be messed around in this way without simply going in to full on sulk mode. Obviously you do this entirely at your own risk, and you will invalidate the forty year old warranty ;~)

[@fritzkinderhoffen2369]

I saw the cable error before you mentioned it :). We've all done that one.

[@gregbetts8057]

if i remember right , CMI hard disks in early IBM AT computers were eventually proven to be junk . i think there is a artificial reef out in california made when they just dumped thousands , maybe millions of them . i have a first gen at with that drive , and can get it to work with the disk setup program , but after running it for more than a hour or so , the information on it became unreadable till you shut it down to cool and start using it again . great vid

[@anthonyhershberger8441]

Any day Adrian posts a new video is a good day

[@smarseille7422]

hard drive 2 sounded like a windshield wiper xD

[@AndyHullMcPenguin]

41:15 probably the antistatic tab grounding on the end of the spindle screeching. Try a little graphite on it. You can use oil (or frankly you can also remove it and the drive will probably be fine).

[@tomiluukkonen4035]

Most (maybe 90% ?) 16-bit ISA MFM/RLL-controllers I saw worked OK with 10MHz AT-bus. Most late 80's models were ok with 12.5MHz. As I remember 13.3MHz was the problem as many failed when used with 40MHz/3 -dividers. Controller worked ok but data was corrupted when transferring to/from HDD. VLB had same problem with 40MHz VLB-bus, it was not reliable :(

[@2010stoof]

It's so funny to me how fast tech moved back then. 87-95 was only 7 years I'm using 12 year old computers now and streaming and everything with them. But back then a couple years were leaps and bounds ahead of prior gen.

[@rah975]

My first drive was 170MB (142MB formatted) ESDI drive made by Toshiba. While not quite as old as MFM, it is just as finicky about being configured right (if not more so).

[@the_kombinator]

Oh damn, I've destroyed my Win 7 partition on my workshop PC (I connect old IDE drives, scan them, read/write to them, format them w/MMC) twice now when doing similar things as this. I now have a switch on the front that shuts off +5 and +12v to it when I work with other drives in it.

[@robertblanchard7053]

Since different mfm drive controllers use different formats, it might be useful to hook up your mfm reader/emulator to analyze the format that was used on the drive to determine cylinders, heads and sectors and also what controller was used to format the drive as some controllers don't use the standard st506 format. It will also allow you to do an archive copy of the flux changes.

[@andycristea]

Aren't those like a gazzillion dollars?

[@CM-mo7mv]

😂 when your doctor tells you "got damaged in the diagnosis process" 😅😢

[@organizmen]

MFM and RLL drives was a pain to handle. I loved SCSI.

[@MrMe4444444]

One time I tried to wreck a hardrive. I used a tape demagnitize. It would pick it up into the air. I would let go of the button and it would drop 6"s to the concrete floor. Didnt faze it a bit. Apparently they are shielded very well. It would boot up just fine

[@neverthehero566]

To quote Alanis Morissette, "you live, you learn"

[@spaniyell]

I'm sure Alex Ferguson once said... Old tech, bloody hell!

[@CheshireNoir]

Q-Edit was a shareware text editor, that was remarkably extensible. I used it a lot in the early to mid 90s.

[@johnsonlam]

Back in the days I've been processing quiet a lot of MFM drive, the computer is not really freeze or hang up but waiting for very long timeout from the hard drive, since they're slow and the timeout period is extra long.

[@jeromethiel4323]

Some early HDD's had a carbon button on the spindle motor, and a grounding brush that pushed on that button. If you wore down to a hard spot in the carbon, the drive would screech at you randomly. Very high pitched, and it would drive me out of the room. Turns out, the fix was just to cut the grounding brush off. And this was from the manufacturer. So we got real used to cutting these grounding brushes off.

[@mikemoyercell]

I just had the same error in spinrite the other day and I keep getting a write fault in dos when trying to format a particular drive. i have my at overclocked - now i will try going back to 8mhz and formatting again. ty for the tip.

[@stvlu733]

I used to double the drive space on these in the early 90's and see how long they would last. It ate up sectors pretty fast since it was probably overwriting the same ones repeatedly. Not even fdisk would fix a fresh start.

[@inerlogic]

The motor was exorting some terque? Oh man! XTree Gold was awesome back in the day!

[@BCProgramming]

With the corruption when doing dir, I had a similar thing occur long, long ago (2003?) when I tried to setup a 286 machine. I didn't have the HDD info so just guessed, and I saw similar corruption when trying to do a dir. I then formatted the drive- which had a load of "recovering allocation unit..." messages, and then installed DOS, but it only worked for a week or so until it started to give data errors. I was in high school at the time so eventually used the school computers to figure out what the proper settings were, and then I was able to format it and it worked for as long as I had it. I suspect that if I had put the correct settings in to begin with, the drive would have been readable, so I think what you are seeing here is a case of the CMOS settings not matching what they were set to when the drive was formatted previously- It wasn't truly corrupted until you did "fix it" in scandisk, I think.

[@stephenbruce8320]

God Bless you Adrian! No way in hell would I ever want to play with those old ST506 or MFM drives. I have a love hate relationship with those drives. My first one was in a Data Chief Hard Drive system used either on a C64 or C128 that had a 20MB Hard Drive and a 1571 disk drive in a case like the original IBM PC. Press two side buttons and it opened up like an old PET. The control boards including the 1571 had hot snot all over the PCB's. Yea that 20mb was a lot back in the day and I was on top of the world using it with my BBS until I upgraded the BBS Software for CNet 128 which no longer supported that Data Chief Hard Drive because it was written to support the Lt Kernal Hard Drive System. Now I was poor and that Data Chief Hard Drive System cost me $500 which at the time was around half the cost of a new one although the last price I recall for a new one was $750. Long Story short I found a way to make that Hard Drive work with CNet 128 and when I posted how to make it work on the Perspective Web Site I became a hero of sorts to those other Data Chief Hard Drive users. I did eventually get a Lt Kernal Hard Drive system which used SCSI Drives because they had a cool multiplexer where you could share 4 computers on one hard drive. I don't remember where that DATA Chief system went but I sold the Lt Kernal to a friend from Kansas but he may have been in Denver at the time, Ron Fink who got into support for XETEK the manufacturer of the Lt Kernal Hard Drive system, but I also sold him all my C128 systems. Damn that was a long time ago. I am into retro computers but not so much into old hard drives but I have a bunch of old SCSI Drives from when I ran a BBS and the live in a draw and who knows maybe one day I will pull them out to see if they still work as I do have an Amiga Collection I could put them into use but then I have no motivation to use them but one day I might take a look to see what they might contain but only if I can find one with a terminating resister which is problem if you just want to look at one.

[@adriansdigitalbasement2]

Believe me I hate them too. LOL! I just try to keep some around working as I have some systems that require them. Back in the day I was always so annoyed when I had to repair a computer with a MFM drive.

[@atlanticx100]

I always remember that cables for hard drives had to be a certain length back in the '80s for timing reasons or am I remembering wrong? My first HD was an MFM. Brings back memories of seeing sectors, heads and cylinders lol.

[@tomaszmarcinkowski8242]

@Adrian on the HDD having issue with track 0, create partition starting with track 1. Use tool like Ranish Partition Manager to leave track 0 out of use.

[@maxtornogood]

Adrian loves 70's & 80's tech until it comes to MFM hard drives.

[@bigdrew565]

2nd Hard drive: Ah, the infamous Computer Memories hard drive. We had an AT at our firehouse that was donated to us by IBM(we had a lot of IBMers in our house in the 80s and IBM had a program where they'd donate equipment to local emergency services, computers, office equipment, stuff like that) it had one of them in it that promptly failed when they were trying to set dBase up on it so we could do our fire reporting on the computer. Failed in the same manner as this drive did. Not the first company that got put out of business doing business with IBM, certainly wasn't the last. They had so much demand for their drives. They just shipped em out without any quality control. So, for 3 months a 5170 sat gathering dust in the Chief's office while our guys tried to tactically acquire a new Seagate drive.