Tube🌈 Timeahh, the HP 9133A - the largest and heaviest external 3 1/2" floppy drive ever built. let's get it working! 🧵
whoops, surprise hard drive inside!
this one is a Seagate ST-506, a MFM drive with a whopping 5MB capacity!
oh yeah, the hard drive has a controller board on top of it. and on the controller board is this super weird potted electronics module. i'll have to look into that later.
the floppy drive is the extremely ancient Sony OA-D31V-1. it's not the first one to come out. more like the second one.
transmissive optical sensors hate dust bunnies. they'll produce false readings, so they must be cleaned!
a single-sided 3.5" drive head is something you don't see every day. they were never that common.
i'm taking it apart this far because the drive mech needs to be cleaned and relubricated. the old grease hardens and makes the mechanism go sticky, so you'll be able to insert a disk, but when you try to remove it, it'll tear the head right off!
and it tests good! the weird 26-pin HP interface is natively supported by my Floppy Exerciser board (https://github.com/schlae/FloppyExerciser)
on to the surprise hard drive. but, no surprise, it won't spin up and pulls a bunch of current on 12v. hmmm.
it spins, but it sounds bad. not much hope for this drive, unfortunately.
the Gesswein MFM emulator was able to capture a flux transition dump! i used their mfm_util to analyze it, and it is a very odd format: check out the command line:
--format EC1841 --sectors 32,0 --heads 4 --cylinders 153 --header_crc 0x0,0xa00805,32,4 --data_crc 0x0,0xa00805,32,4 --sector_length 256
@dgesswein , who authored the MFM emulator tool i am using for this task, reached out. i updated the software to the latest version (i was tragically out of date). got a new dump. only a few bad sectors this time, and none on track 0!
bad sectors were on tracks 37, 75, 113, and 152. the 9133a uses hardware partitioning to get four logical volumes, so these "bad sectors" are really just extra sectors at the end of each disk.
for posterity, the command i used was
./mfm_read --format Xebec_104527_C0_256B --sectors 32,0 --heads 4 --cylinders 153 --header_crc 0x0,0xa00805,32,2 --data_crc 0x0,0xa00805,32,2 --sector_length 256 --retries 50,4 --drive 1 --xebec_skew --begin_time 151000 --tran hp9133a_st506 --ext hp9133a_st506.bin
'file' is superintelligent these days. it knows about LIF disks! looks like the binary data is good!
also the drive is running very smoothly now. a few days ago it was making horrible screeching sounds but i think that was the spindle bearing.
i've been running it upside down to allow the oil to warm up and drain back into the bearing.
digging around on this drive, i've found a bunch of software for the HP-85, including a program designed to control the HP 5005B Signature Multimeter. presumably none of this stuff has ever been preserved before.
Linker3000People used to laugh when I said I'd fixed their squealing hard drive by oiling it.
Seagate used to have a grounding strip that sat atop a bearing on the end of the spindle (outside the drive) and at a push you could apply some graphite from a soft pencil to stop it being noisy.
Happy days.
Briala
Poul-Henning KampMy AutoArchaeologist toolkit can turn the LIF filesystems into static HTML files so you can spelunk the contents.
Example:
https://phk.freebsd.dk/misc/fatfs/05/056ab17c6.html
Software:
@bsdphk useful, can it handle partially corrupted images?
I dont know how robust the LIF excavator is, I have only written/tried it on good images, but the general idea of AA is to handle whatever you throw at it, as well as possibe.
The fastest way to find out, is probably if you send me the image, but I can also walk you through the setup so you can run AA yourself.
(I've never finished the proper python packaging so it's a bit manual)
@bsdphk i'm going to try and get a better image file, then i will give it a shot.
Traceback (most recent call last):
File "/home/eric/src_other/AutoArchaeologist/run_example.py", line 11, in <module>
from autoarchaeologist.container import argv
File "/home/eric/src_other/AutoArchaeologist/autoarchaeologist/container/argv.py", line 17, in <module>
import ddhf_bitstore_metadata
ModuleNotFoundError: No module named 'ddhf_bitstore_metadata'
Sorry forgot to mention that dependency, that repos is also on our codeberg account:
@bsdphk ahh that solved it. new issue though, it looks like this hard drive image has 4 volumes but each has lifver set to 0, and the volume header is missing the track, head, and sector count fields, triggering a bug:
dgessweinWith some effort it may be possible to recover more if its just heads were pulled out of alignment when they were stuck.
https://www.pdp8online.com/mfm/microstep/index.shtml
If you want me to take a look at your transitions file to see if I think that method may work send me a private message.
Barry@tubetime Don't feel bad. I had a Data General Nova at work that I used to collect and process data from flight testing. One day, the machine made a sound like bad brakes. I asked one of the admins, who said, "Oh, yeah. That happens from time to time. We always lose a bit of disk space when that happens."
mbpaz
Y⃒̸̷̝̜̙ͥͥͥngmar@tubetime Tap on the side with a hammer often sorted that. 😅
🇺🇦 haxadecimal 🚫👑@tubetime
Maybe it just needs some Head and Shoulders (TM).
Maybe it just needs some Head and Shoulders (TM).
SLeiBt@tubetime Had a disk that was working great and the next day, it wouldn't start. Tried a few things with no success. Bought a new one, cleaned up the surroundings as best as I could, opened the lid a little & tried not to get any dust in there, helped the motor a bit and it was up & running again, I could copy the whole content. As an experiment I left it running, monitoring the errors. After 2 weeks, they started increasing. Not unexpected when you've been to HDD plant's clean rooms.
@tubetime So my take for anybody reading this and tempted to open their HDD: don't, unless you are curious & about to toss it or desperate for the data. In the later case, if it works to make it spin again, be ready to export all data ASAP. Just about any dust is larger than the distance the heads fly above the disks, thus scratches to the magnetic surface are a given when anything gets trapped in between. There are reasons for cleanrooms, coveralls, air showers... during manufacturing.
DrScriptt
Chip
Dantali0n 
Marcin Wichary@tubetime Is that like… 360KB capacity?
@mwichary worse, it is 270K and it uses 256 byte sectors. it also runs at 600 rpm!
~n@nblr @tubetime Probably regular disks? But the earliest ones (I think just the OA-D30V but I’m not sure) used disks with a latching shutter. https://www.jamiecraig.com/early-floppy-disks/
I’m pretty sure there was never a flippable 3.5” disk.
Stewart Russell@bytex64 yes, those are the disks I remember from the early desktops that my dad's HP dealership sold
@tubetime
Apple sold tons of 3.5" single-sided drives (Sony mechanism, but special for Apple, because... Apple.)
They were uncommon in PCs.
Apple sold tons of 3.5" single-sided drives (Sony mechanism, but special for Apple, because... Apple.)
They were uncommon in PCs.
@tubetime are these from the time that 3.5" disks had shutters with rounded apertures, and the shutters latched open? I remember some of my Dad's HP kit was like that
bitsavers.orgit was made by an OEM that spun off xebec
@bitsavers that's wild
Neko May
SnoopJ