A Day of Fun With MFM Hard Drives!

[@MajenkoTechnologies]

It is true! We programmers make better lovers. In fact I made one just the other day, and it only crashed three times.

[@klocugh12]

It's soo easy. PEEN_LEN = 6; REPEAT IN PEEN_LEN; OUT PEEN_LEN; UNTIL CLIMAX;

[@tezinho81]

Having it go down on you only three times must have been disappointing

[@FloridaMan02]

At least your stack still overflows

[@therealjammit]

This works for me: alias sex "updatedb; locate; talk; date; cd; strip; look; touch; finger; unzip; uptime; gawk; head; apt-get install condom; mount; fsck; gasp; more; yes; yes; yes; more; umount; apt-get remove --purge condom; make clean; sleep"

[@TheMightyOmega-NotTheAlpha]

You know, you voided your warranties on those drives you opened.

[@RichardFraser-y9t]

I think they may be out of warranty by a little bit.

[@juergenschimmer960]

@@RichardFraser-y9t Just a little tiny bit - not even a century

[@UsagiElectric]

I actually took footage of me slicing the warranty sticker on all three drives, but it didn't make the final cut.

[@TheMightyOmega-NotTheAlpha]

⁠@@UsagiElectricI don’t know why, but whenever I need to open up old electronics, those “warranty void” stickers always make me hesitate, even though the warranties expired decades ago.🤪

[@der.Schtefan]

Usagi: "I am bad at UNIX" Also Usagi: "Here is my PDP-11" :)

[@UsagiElectric]

Totally going to install RSX-11M on it so I can be bad at multiple operating systems!

[@neilbarnett3046]

@@UsagiElectric Are you bad at RSTS already?

[@rick-lj9pc]

The Gesswein is a true emulator- it was designed to be able to image a failing drive then remove that drive and emulate it with the image you read, the docus claim to support emulation on a ?Rainbow! You should test if the Rainbow can boot replacing the HD with the Gesswein emulating the HD. If it won't boot, or only boots MS-DOS/CPM you would know the image isn't 100% good.

[@rivimey]

In linux, "cat filename| less" can be replaced with "less filename ", which is slightly better too. I was hoping you could read the image files as a filesystem, partly because I too have cpm floppies to read. You can make a block device from the file using"losetup" (though "mount" will do it for you when it knows it should), but i don't know of a cpm partition table or filesystem for Linux 😢

[@CC-ke5np]

And if you desperately want to "cat" the rainbow file, you can always "lolcat" it. You may need to install lolcat first. This makes the rainbow file really rainbow!

[@vincent_sz]

Or better without the temp file: "strings filename | less"

[@isatty]

cpmfuse supports CP/M filesystems using fuse (userspace filesystem). Or you can use cpmtools

[@itogi]

Advice: You can look through your command history in Linux console with Up and Down arrows.

[@grishka212]

To add to that: you can use the tab key to auto-complete file paths.

[@phill3986]

Control r to reverse search through command history

[@drstefankrank]

and copy/paste in a terminal exists. :)

[@tezinho81]

And type the command 'history' to see a full list of remembered commands. If you type your password into an open prompt by accident, you can use the same command to clear individual entries.

[@UsagiElectric]

Thanks! Though I did already know that shortcut. When I'm doing screen capture for a video I always retype the full command so that it gives the viewer, especially those not familiar with Linux, time to visually locate the command and mentally parse what is being typed before it flies off the screen.

[@ajlitt001]

The glass plate in the RD52 is the servo position encoder.. If you look closely at that arc pattern you'll see tiny metallic stripes.

[@douro20]

It's called the "Light Positioning System". These drives have a servo surface but it is actually possible to configure them to ignore the servo surface and just use the LPS for tracking.

[@mikefochtman7164]

I noticed a 'void warranty' sticker on the top cover right above that sensor. There may be a way to adjust that sensor alignment with the cover installed for final checkout. If could find some old instructions MIGHT try realigning it.

[@Zekrom_64]

Interestingly, some of the strings in the Rainbow's drive for the startup menu seem to have ANSI escape sequences in them ( "[;H" moves the cursor to row 'n' colum 'm') which must be used to lay out the menu on the screen. Some of them also look to be dollar terminated (ending with a '$') meaning they are probably intended to be passed to standard output in MS-DOS, and are then processed by ANSI.SYS (or some variant thereof). However, that would require DOS to be loaded in the first place, so I wonder if this functionality is supported directly in the BIOS...

[@TSteffi]

I didn't know that DOS also used $-terminated strings. But I know CP/M does. So maybe DEC just used what was common back then. CP/M 3 introduced a BDOS call to change the terminator, sou you could use 0-terminated strings instead.

[@mikefochtman7164]

Quantum drive with that 'wind gauge' is kinda neat. I bet that black plastic arm is detecting the 'wind' near the platter surface and is an 'unlock' signal to let the heads move from the landing zone. I notice a 'void sticker' on the cover right above that optical sensor for your plastic piece. Bet there's some way to adjust/ align that sensor with the cover installed for final checkout. If you could find some alignment instructions and put a scope on some head output, you have a chance to realign it???

[@alexanderdelguidice4660]

In the default terminal of most linux distributions, bash, you can press the up/down arrows to select a command that you previously ran and the enter key to run it. The up arrow selects the next one in the list of previous commands, the down arrow goes the other way in the list.

[@MajenkoTechnologies]

@@alexanderdelguidice4660 also ctrl-r will start searching the history. Press that then start typing a command and it will try and find the best match in your history to fill the rest of it.

[@v12alpine]

DOS prompt too, at least on Windows.

[@douro20]

That first drive looks like a CDC/MPI/Imprimis one, particularly a Wren II which was a very advanced drive for the time. They were made with ST506 (they called it CDC506), ESDI and ATA interfaces. They were apparently the first company to ship a drive with an ATA interface. You are fortunate to have two which don't have bad tantalum capacitors. If they have Seagate branding it means they were made after Seagate acquired Imprimis in 1989.

[@CC-ke5np]

Use the TAB key to enter complicated stuff and navigate through directories much more easily. Type the first few characters and hit TAB. The console will fill in the command or directory name as far as it is unique. If the command or name isn't fully autofilled, hit TAB twice to see a list of the possibilities. Then enter the next character and hit TAB. For example cd /opt/mfm/ TAB TAB will show you all the subfolders in /opt/mfm so you can add them while typing the cd command. You don't need to ls any more! No typos, fast and it also works with parameters for more modern commands.

[@RonLaws]

Perhaps Programmers do make better lovers, It's only logical. 😏

[@JamesLewis]

Hey there... don't give up on the drive with the alignment optic thing quite so fast.... I don't think those drives have any permanent index data on them, if everything is working, you might well find the a simple low level format will fix it... I did this once back in about 1994 for a bet, and actually removed the heads and all the platters from a drive, literally cleaned them with window cleaner spray, put the thing back together and got it fully working again after a low level format... where, in fact, no bad sectors were found,

[@ownpj]

<a href="#" class="seekto" data-time="435">7:15</a> Do these drives automatically park their own heads on power loss? Asking because back in the day when I had a full height drive (i dont rememberwhat type it was) I had to run a park program before powering off.

[@ub321]

I was wondering the same thing. Were any MFM drives self-parking?

[@Alexis_du_60]

Yes, there's the ST-251 and it's other brethren (ST-277R, ST-296N, ST-251N...)that automatically parked the heads. I think the ST-4096 also did (?) since it had a voice coil mechanism with a return thing

[@neilbarnett3046]

I recall using the PARK command as a precaution. The problem is that if your drive has just lost power, it has no power to park the heads. Drives that had voice-coil positioning would have a large capacitor to park the heads with its "last gasp". This feature was actually a problem on some large format drives, one 14" drive that I used to work on was able to do an emergency retract while the engineer was doing an alignment on it. This broke the alignment tool, misaligned the head you were adjusting and, if you were in the wrong place, broke your finger.

[@billj5645]

I remember back in those days, around the middle 1980s, MFM drives were common in PCs, larger drives were ESDI or sometimes SCSI. Drives were very expensive so sometimes we would scrounge up broken drives and have them repaired. Broken drives would sell for around $1 per megabyte, crazy by today's prices. My first PC had only floppy drives, I later bought a 20MB hard drive kit for it for $450 from a tiny little store in Austin, TX called Compuadd. I eventually added a 2nd 20MB drive to that PC, then replaced both with a 60MB RLL drive. My next PC was a 386 with 120MB IDE drive. Then I built another machine and eventually it had dual 383MB ESDI drives. That was in the early 1990s. Today my desktop computer has a 1TB SSD and a 4TB SSD. The 4TB SSD is 200,000 times the size of my first MFM drive.

[@halitimes2]

Another useful command is "od", basically octal/hex/etc viewer on command line. Pretty handy.

[@NathanAllworth]

Baby Bun is adorable.

[@gammarayflash1170]

Try to find identical harddrives and then swap the outside electronics.

[@OscarSommerbo]

Nobody tell Usagi about tab completion.

[@ExtremeMetal]

Keep copy/paste under wraps too

[@soundguydon]

Back in the early 90's (maybe around 1993 or so?), I had an old 5 1/4" full height 80 MB drive. Looong before KZbin, and I hadn't even heard the word "internet" yet. I was very curious, so I popped the top off the drive and ran it for quite some time, bare. I don't remember much, just that it was built before voice-coil head movement, so it had a stepper motor to move the heads. The whole desk vibrated when the drive was seeking, and it fascinated me to watch it dance across the platters while booting, loading programs, etc. (However, my first hard drive was a full height 20 Meg drive on an XT. That could make the desk shake too!)

[@semuhphor]

Tres cool episode, Mr. UE. ありがとうございます

[@UsagiElectric]

Thanks!

[@NikolaiKostadinov-dc7jq]

You mean RLL drives, right?

[@UsagiElectric]

Heh, you're absolutely right!

[@wmrg1057]

We had to clean the spindle ground on HP 792X drives back in the late 70s. Weird sounds were normal when dirty. Basicly dirt on a beating point.

[@the_kombinator]

I removed one out of a DEC rainbow - a Type 1 MFM, 10 Mb of capacity, along with its controller card. I put it in a very early AT machine and formatted it - it worked, zero bad sectors. I was blown away that it actually worked, being from 1981, it's older than me.

[@johnvanwinkle4351]

Great job getting the data off those drives. Look forward to seeing you fix the others.

[@David-h5r1x]

It's too bad MFM hard drives are so unreliable they are such cool looking drives

[@maskddingo1779]

St-506 is a 5mb drive. I have 4 of them.

[@RinoaL]

Man I haven't seen a beagle bone in a long time. When I worked at Apple we used them for our prototyping system, my coworker who is a programming legend built a system to network them and send commands called "Shotgun" because it would shoot data to each and they'd do your bidding in the system. Meanwhile I named my system that worked under it T.A.C.O. because we were near a taco bell and our supervisor thought that was stupid and vetoed that. lol

[@Darkstar2342]

<a href="#" class="seekto" data-time="1377">22:57</a> that plastic piece not only has start/end markers but also the servo information on it (the grey-looking circle-segment) so without that in proper alignment, no tracks will ever be found by the drive again

[@JamesLewis]

I realise that there may be some sensitive data on the ~80 meg images, but what about the 10 meg one?... I'd love to have a go at locating the partitions in that image and mounting them on a modern system, so if it doesn't contain anything sensitive, please let me know if that would be possible. If not, I'd still like to give you some things to try on your Linux laptop to the same end.

[@maskddingo1779]

Most of my mfm drives that use servo tracks no longer work. They behave similar to that cdc one. Those that just use stepper moters are still generally work.

[@Bastler95m]

you could have used tab to autocomplete the filenames that already exist and then just change the extension on the end when you want to store it as a different format.

[@anotheruser9876]

@<a href="#" class="seekto" data-time="1012">16:52</a> Flashback to "tickling the tail of a sleeping dragon".

[@AsbestosMuffins]

Can't really make it to the LSSI in the next few months but its absolutely on the list

[@kevinmerrell9952]

Great episode. Nice doorstops and boat anchors!

[@jarthurs]

I was looking at them thinking, they'd make a great heavy base for a retro desk lamp.

[@thegeforce6625]

that Quantum drive is a Q540.

[@LongSteve]

Programmer here, I hope my wife of 20 years would agree, we’re not too shabby in the lover department. Is there any way to boot the Rainbow from the image of the drive you made? I understand you can see and read some text data from the backup, and that’s often enough. But I think when it comes to a machine like this, you want to be able to restore some bootable media in the event the original drive fails. I’d love to see how to test the image and see if it really is legit?

[@mackal]

should have done strings foobar | less

[@TheDiveO]

quantum drive, that's the optical ruler, you will have a hard time calibrating if ever, sadly.

[@The_electronics_nerd]

hi usagi i love your videos

[@richardperritt]

Drive spinning down shortly after spin up could be an RPM failure. If the drive doesn't reach it's expected RPM with a specified amount of time it's spun down by the drive's onboard controller as it's considered defective.

[@kpanic23]

Yup, can be caused by either mechanical or electronic problems: Either the spindle bearings have too much friction to get the drive up to full speed or there's some power related issues. I had driver issues, where the spindle motor was missing a phase, or simply bad capacitors causing the spindle motor not to have enough power to reach the correct speed.

[@PlayerClarinet]

The Tab key in most Linux shells will automatically complete file names for you. Much typing saved.

[@tezinho81]

Hitting it twice will show all available options for autocompletion

[@goofyrulez7914]

My friend is always trying to get me to switch to Linux but he is a computerphile whereas I just use my computer as a tool. As long as it does what I need it to do, I'm happy.

[@johnps1670]

Linux sounds like a complete tool box.

[@gtb81.]

some programmer has been waiting decades for you to find that message!

[@CATech1138]

some where some old guy got mystery wood when that egg dropped....it would be evdence of a just god if he got know it's been found and seen by the whole HELLORD world

[@oidpolar6302]

How about the low level format the one missing index pulse?

[@jwhite5008]

how could that work without an index pulse?

[@oidpolar6302]

@@jwhite5008 emitted from the plate or from the motor sensor?

[@jlforester]

I never knew about the LSSM. It’s only a couple hour drive from Morgantown. Definitely coming for the event. My college had a Prime mini (mid 80s) and my first coding job after college was in Pittsburgh at USS on IBM 3090 Big Iron.

[@stonent]

Well if the bad drives appear the same model and revision as the good ones I'd go with a board swap to see if that brings them back to life.

[@Electronics-Rocks]

OK it has been 34 years but I worked in HD recovery/ repair. On the MFM & RLL drives with index pulse & timings not working it will need to be replaced with the manufacturers software & only certain controllers will work! Like the MSDOS command debug g=c8<a href="#" class="seekto" data-time="5">00:5</a> Reset the info but if totally corrupted it will fail. Then in MSDOS fdisk places your OS boot code MSDOS.SYS & IO.SYS. Then the Format command to set up FAT. Problem is the codes to control the drives to place the timing marks (Sector & speed)

[@russellhltn1396]

I wonder how well that power supply you were using was doing? Some supplies need a normal current draw on the +5V to throttle up the switcher to provide rated current on the other voltages (like the +12V). Some drives need quite a bit of +12 and that Beaglebone probably isn't drawing much on the +5V.

[@adamw.8579]

A small tip for old MFM disks usage - they must be parked before power off, otherwise heads lands on usable platter area and scratches it. For Seagate drives parking area is seek to few tracks above maximum usable format (most close to center of disk). For others disks maybe different, some later disks have separate command for parking operation accessible by controller BIOS.

[@neilbarnett3046]

You may find that the noise is not the bearings, but the spindle ground tag. This is copper or bronze, with a carbon pad that rests on the tip of the spindle and it chatters when the drive gets old. The fix is to run the carbon pad over some wet-and-dry paper, but the noise will come back eventually. Oooh, rectangular LEDs with a white surround, that takes me back. In fact, I think I have one somewhere in my "things I never threw away" box.

[@CATech1138]

in the early 90s, Imused to open, replace bits, run, diagnose and relid ESDI, MFM and early IDE drives without a care beyond don't touch the disks

[@oswaldjh]

Haven't heard a word about MFM drives since I upgraded an IBM XT with one from one of the first big box computer stores in the 1990s. These early stores were a wealth of information and tips since this was pre-internet. If I'm remembering correctly the drive was a full height with 10MB of storage. This was back in the 640 KB RAM days.

[@jarthurs]

I love these full height 5.25" drives, memories from my early days of PC ownership. Buying a batch of untested ST225 and going through them to find working ones. I was thinking they'd make great ornaments, but trying to find even broken/untested ones on eBay is really expensive.

[@jwhite5008]

Pressing TAB will auto-complete paths and sometimes other stuff in Linux To copy and paste use mouse. Middle-click usually pastes selected text, Ctrl+Shift+C and Ctrl+Shift+V copy and paste from the terminal window (since Ctrl+C is usually SIGINT), or use terminal window menu. Please don't run hard drives when they sound like the 1st one, you're very lucky the bearings didn't overheat and permanently sieze. The problem with the spinning down drives is likely electronics or wrong RPM due to old motors. Scratches on the platters might prevent it from reading or it might just have a LOT of bad sectors, but I don't think that would cause it to spin down.

[@MrBradleykeith]

As far as I can recall, the Winchester disk drives did not have servo platters, the track and sector positions where encoded as preamble data when low level formatted. Also in those 5" drives there where both MFM (Modified Frequency Modulation) and RLL (Run Length Limited) types and they used different types of controller boards, they were not interchangeable.

[@jeromethiel4323]

In my opinion "spinning" rust was as influential in early computers as the transistor. Storage was always the biggest issue with computers in the 60's and 70's, and magnetic media was the answer. We are so spoiled today with super cheap mass storage.

[@matthewday7565]

If the plastic is the tracking guide, maybe it would take a low level format?

[@Putersdcat]

You need the glue for reattaching a rear view mirror to a windshield. Autoparts store. <a href="#" class="seekto" data-time="1428">23:48</a>

[@denniseldridge2936]

This was such a cool and interesting episode for me as I was weaned on ye olde MFM drives, back in the 80's-early 90's. At my first tech job I cobbled together an 8088 system, and was actually running a 5 megabyte Seagate for some months with the cover off(!). Never had a problem and only stopped using it when I upgraded.

[@AiOinc1]

Nice CDC BJ7D5A in the thumbnail there

[@kelli217]

I’m kind of surprised that there isn’t already a boutique industry in recoating old hard disk platters to repair head smacks. Not crashes… that’s usually too much to fix because they often create grooves in the platters.

[@russellhltn1396]

I think that grounding strap is intended to have a carbon button on it and not metal-to-metal. That's where the black gunk came from.

[@jorgeferreira6727]

You don't have to retype that crazy command line options. Even in terminal mode you should be able to "copy & paste" it.

[@itstheweirdguy]

That's so cool it emulates the mfm hard drive as an mmc storage device. I only do sd's and nvme's in linux! We're so spoiled now.....

[@jagdtigger]

You really should try to give linux a chance, it has a learning curve but it more than worth it seeing the direction MS is taking with windows. (I dipped my toes into linux back when ubuntu 8.04 was actual, and went full time when i have seen where ms is heading with 10 and their disregard to users by packing ad and spyware in updates for 7.)

[@ImTheReal]

5.5k visualizations and only 900 likes WTF?!

[@c1ph3rpunk]

Making better lovers, ok. What I wanna know is what the #SM3 by it means, hashtag Shaking My ….. 😂 I’m afraid to see what that stands for nowadays.

[@jamesburgess9101]

is there a way to convert those raw files into something you can just mount?

[@jakobfindlay4136]

Im pretty sure i saw daves garage using this same device to load data onto a pdp-11

[@EinChris75]

"Useless use of cat"... less can read files directly.

[@TonyCR1975]

Lets hope you get it fixed soon!

[@zacharysandberg]

We need some MFM ASMR 😀

[@unmanaged]

you know you cab use a mouse in the console

[@Sumppen]

I do love the sound of mfm/rll drives

[@frankowalker4662]

At least it was easy to fix the squeal. 😄

[@shmoopfox3652]

Thanks for the vid!!

[@Evergreen64]

That sound, in my experience, is not a bearing. That is one of the platters. It sounds like a head is not in a good place and one of the platters is chattering. And as a Linux/Unix note, MAN is your friend. A manual in the OS. If you MAN anycommand you will get a nice description of what that command does and all it's switches. It's how I started learning UNIX in 1983.

[@JoCrt]

Fun video, thanks

[@retiredwizard]

Great episode! Since you successfully backed up the data from two of the drives I would have loved to see you lay the Rainbow bits back down on a different drive and bring the Rainbow up on different spinning rust (or even boot using the MFM Emulator if that's an option?). I've never used the MFM Emulator, but the errors you saw at the end of the Rainbow backup remind me of errors that the Greaseweazle displays when it encounters certain types of copy protection. I don't believe the copy protection scheme is transferred in those cases so actually testing your Rainbow backup might be a good idea. Thanks for all your awesome content!!!!

[@timradde4328]

I have a Rainbow and did just this. I used the MFM emulator to image the disk and now use that emulated disk in the machine. It works just the same. The MFM emulator is fantastic. I need to get a 2nd so I can image my Pro-350 disk.

[@andrewdunbar828]

in the recent future

[@greenerell484]

cool

[@simonstergaard]

LOL...not the first time you connected a connector wrong...

[@UsagiElectric]

But, it's the first time I've connected *this* connector wrong!

[@NateEngle]

Wow, I spent a lot of time with MFM drives and I don't recall ever hearing one that bad that was still working. One thing I bet is the case is that this one spent a lot of time at a significantly higher ambient temperature. These things are from a time when that thermal expansion was kind of expected, and back in those days we didn't have a standby SSD to fall back on when the MFM device started making us nervous. In other words, we were always nervous.

[@TechnikZaba]

Why you did not park the heads?

[@matthiasmartin1975]

Thanks for using Debian Linux on that laptop, really helps to keep the level of coolness relatively even throughout the video.

[@edgeeffect]

If you want a GOOD "MFM" drive, you honestly can't beat an ST-225. They're as slow as hell but you could use one as a football and it'd still keep it's data.

[@greenaum]

Just a note, "Large Scale Systems Museum" is a very boring name, and not particularly descriptive. I'd put "mainframe" "computer" and "gigantic old" in there. Maybe "1950s" and "1960s" too. I'd probably remove "Large Scale Systems" while I was at it.

[@jeremiefaucher-goulet3365]

if it's a law to spin an open drive, then it should be sin to open a MFM treasure that might only be having an electronic issue or experiencing easy to dislodge stiction.

[@HesselAnnema]

No head parking?

[@BonkedByAScout]

don't ever do the drive bearing audio again please, dub over it or something or just mute it. My dog hated that.

[@AxelWerner]

#LINUX is THEe OS of the past, the present, and the future. There is nothing like it, rather than it's grandaddy #UNIX . Windows and Apple is for the uneducated. UNIX/LINUX for the PROs.

[@JanBruunAndersen]

RT-11 was pretty good. VMS was good too. AOS/VS and AOS/VS II was not bad either. AIX did its job too. SunOS was fun. Solaris was heavy. FreeBSD was stable.

[@MrStevetmq]

graphite past. HDD bearings

[@unmanaged]