You wondered about the torx screw on the actuator. I did not design the system but my analysis, from a ME, is that the assembler would tension the ribbon with a gauge, dynamometer if you want, and then fix the ribbon with the screw. This makes sure that the friction between the ribbon and spindle is just right, not too loose and not too tight. Simple mechanics for you EE types. The problem being that you don't want the ribbon to stretch and lose indexing and not to slip for the same reason. CBS
Sadly, this does not even compare to opening one of the original 10mb drives that was 4x the size. In order to get it to spin up, sometimes you literally had to spin the hard drive disk like a DJ.
I took one of these, a 5 disk platter and and two current drives to a career day presentation. I numbered them and asked the students to Id the hard drive disk storage. No one picked them all. (You can see them in this profile pic)
Take a few of the platters and make wind chimes. Though they will all be the same note, they will be unusual. Put the platters on a pole, attached with string or wire, and the reflections will keep birds away!
The Seagate 50mb was a long way along the development path of hard drives. to see where we have really migrated from you need to look at the originator of the 5.25 HD. This Seagate was sleek and advanced compared to the ST506 or ST412. Most people don't even know who Shugart was.
I got my first ST-251 with a 10mhz XT machine. I got a DTC7287 RLL controller card and made the -251 a 60mb drive when I upgraded to 286. Those were the days when you could back up a HD onto about 40-60 1.2mb floppies with PCTools backup. Eventually had 2ea -251's in RLL and a MicroScience 65mb RLL drive. Even ran Stacker with the MicroScience drive and a -251 RLL with a 386sx Mb machine; made right at 180MB with Stacker. -251's were popular drives and sticksion was a big problem; we all knew how to drop a drive a couple of inches to break the heads loose from the platters.
I did my vocational training in a company repairing hard disks - I can't remember the capacity but 20Mb seems to ring a bell (It was in 1983 if that helps). We had a clean room and had to change the platters if they showed too many bad sectors on the test that were run previously... yes, I managed to kill (at least) one drive by forgetting to remove a resistor pack from it before connecting it to the test device! Nothing changes!! :-))
Wow! That was great and just think we throw them away. They are very cheap and i guess the robots do the manufacturing. Seems to do a lot of people in the recovery business. P
You forgot to mention the error list on the white label on the cover of the drive. Back then, you had to "low level" format every new hard drive. That formatting required that you enter a known list of bad sectors on the hard drive. This process took forever! Today of course this is handled by the programming on the special chips on the drives themselves. In fact, drives are not even low level formatted any more. All data work is done on the fly with the new controllers on drives, and errors are handled and data moved, never to be noticed by the end user. Pretty good advancements for hard drives, eh?
Hi, I became Vice President of Engineering in Thailand for Seagate during the ST238R era, 1987-1989. The 238R platform was the same as the 225 platform, the difference being that the two drives used different circuit boards containing RLL (Run Length Limited) or MFM (Modified Frequency Modulated) circuits. The 238R was 30 MB formatted, the 225 was 20 MB formatted. Both contained oxide media. I introduced thin-film media to these drives, as I am a co- inventor of early thin-film media. The new drives containing this media were called the ST277R and the ST251. The 277R was 60 MB and the 251 was 40 MB.
This brought back memories of the days when I HAD to know everything. For instance: MFM: Modified Frequency Modulation RLL: Run Length Limited Park your heads! Stepper motor vs. voice coil actuators And of couse, all the jumper positions on the controller card. Ahhh the good ol' days, when you could learn all about something *before* it became obsolete *sigh*
Would seem the drive is about 9 years newer than the processor. "Back in the days" 1991 for drive. 1982 for the 80286. Can I get a job @ TechRepublic? I have many "old" things I can take apart and take pictures of. LOL I could spend DAYS on Flea markets and dissecting old technology.
Used to do this years ago when the drives died from hard crash. Would take the platters out and make them into interesting clocks for fellow technoids. Since I was a service manager for the original parent of CompUSA, used to have an unlimited supply of drives. KD
It was... very nostalgic. Seeing this old hard disk. Reminding us of a time not-so-long-past when 1 MiB of memory is all you need, and 16 MiB of RAM means you're a god :D I see all other commenters are nostalgic like me :)
This was very cool, I worked on drives similar to this and older CDC sealed drives with up to 80mb Pacs that would be inserted and twist a handle to remove the outer cover to install. It was amazing because the heads were 4-5 inches long and to repair you could regularly tear the whole drive down to the aluminum core. Oh yeah, the coils were 3 inches in diameter too and 5 -6 inches long.
If you'd really like one, I still have at least one 8 bit controller card for these drives - if you had a mainboard that could use one....
the actuator motor in this and other old harddrives are stepper motors. I have a old ST4096 opened on my workbench beside others in different sizes and from different era's. A 80287, a 486 and some old Pentiums are there as well, showing their bare silicon. The ST4096 had 96MB unformatted and we used them in Novell servers... They cost substantial money in their time, considering the 8Gb micro sd i just bought for some 60$ for my Sansa MP Player. It has a total of 16Gb now...
If you think this drive was big, what about a Priam 60 Mb, full size double height 4 plates??. That was a real big baby for the time. I had an AT with 2 monsters and it ate every drop of current the power supply could generate.
The actuator motor is called a stepper motor. The number of pulses sent to it would determine how much the motor turned so you could control where the heads were positioned over the platters. Peder, and old computer guy
I believe the head positioning drive motor is simply a common stepper motor. http://en.wikipedia.org/wiki/Stepper_motor
I've been cracking open old drives and putting them in "shadow box" frames: http://www.a-hi.com/art.html Check it out...
The old single sided single density Shugart SA 901, 8.25" is what I cut my teeth on when I started in the computer industry
There was a stretch about 6 year when over %60 of the drives that I worked with were the ST251! Thank you for providing for this doubling of capacity in the same form factor so many years ago!
I worked in the clean room repairing ST225,ST251 and older drives in the Delray Beach Florida facility during 1987-1989. Stiction was a big problem, lots of the drives had the heads glued to the platter. That was just about the time when 3 1/2" drives were appearing. In that same facility we also repaired ST412 (10MB) and even some ST506 (5MB) MFM drives. Thanks for a great thread.
Thanks, dogmas47 PC techs from that era (and now) thought that ST238R and ST225 used the same logic boards, as did the ST277R and ST251. One could always format an RLL drive with an MFM controller to end up with a drive at 2/3 the capacity. Many tried to format the lower capacity MFM drives with an RLL controller to get the capacity of the similiar "R" model, and sometimes this worked for a while. Until you posted this, many of us believed that an ST251 was simply an ST277R that was rejected for media that wasn't reliable enough, and that ST225s were ST238Rs rejects. I became so familiar with these drives that I could identify them in the case by the distinctive sounds they made spinning up or spinning down. I described the ST251 as sounding like an egg beater.
My XT came with a 10MB hard drive - it was great. No way was it conceivable that some day there would be 10GB hard drives in PC's let alone TB drives. It was all DOS, Baby.
16-bit AT slots paired with a modern (for 1997) EIDE/ATAPI card gave this machine a 2.1 GB hard drive and an 8x speed CD-ROM drive. It can support more, but it doesn't need any more. Of course, all it can do was play QBasic games, audio CDs (through it's Sound Blaster Pro), and program HAM radios. All DOS, no Windows.
My first PC had a 40mb NEC drive that had been paired with an RLL card to give 60mb! This was back in 87 or 88, and my daughter is still using the keyboard on her computer now. Its looking a bit yellow and weighs a ton, but still works perfectly.
i remember having ST251 drives in 286 PC's. But 386-16 were already on the market at that time, but quite expensive. The fastest 286 i remember ran at 20 MHz. Not in 1982 of course. And there was less bloatware on PC's and antivirus was optional for most users.
Back in the day, I had no money, and when the first IDE drives came out I had no money for them, so I got some older RLL & MFM drives. BIG, Clunky, slow, BUT they worked. Lots of bad sectors, but they could be skipped. To me, Windows and mice were cheating... you should've been able to do everything from the command prompt. When I absolutely possitivly had to use windows, I learned to do it from the keyboard. Finally gave in when Win95 beta came out. got my first IDE drive and mouse. sold out...
I remember my Commodore Pet from 1979 with 64kb of address space taken up with 32kb of PROMs containing the operating system such as it was and a Basic Interpreter plus 32kb RAM. A cassette tape drive held my programs. A friend could write EEPROMs so we added our own bits of 6502 assembler program in the gaps left in the PROMs so that we had an enhanced performance. You really got to know your computer in those days.
I got rid of one of those a few years ago - it took two of us to lift it onto a pallet for disposal, those things were real pigs. The heads were positioned using voice coils inside a magnet (those are the 3" x 6" coils you refer to). The one I got rid of suffered a head crash at speed - it made an awful squealing noise before it came to a final stop. Gave the term "disk crash" a whole different perspective. I replaced it with a 1 GB SCSI drive that was pocket-size in comparison.
No that was FULL height, everything now is half or even quarter height. In the olden times Seagate used to label their drives as ST (Seagate), a 5 or a 2 (5 indicating 5" height a 2 (2.5 or less) then the UNFORMATED capacity of the drive. A Suffix of nothing indicated a MFM, R indicated a RLL, and a N indicated SCSI (Why I don't know).
The "unusual" (by today's standards) band that translated rotary action to semi-linear was used a lot in 5.25" floppy drives of the day. I suppose I should chuck all my old 5.25 disks, as it's unlikely they are still readable, even if I had a drive and OS that would support them.
60 MB, floor-standing upright tower, sounded like a jet engine winding up. In the day, we thought it was so big that the government wouldn't be able to fill it. And I remember the 8" floppies - DS/DD was a whole meg on one disk! Wow......
You were forced by the market to use a GUI environment. In a CLI environment you are talking to the machine, much like in the MFM/RLL/ESDI days you were communicating with the drive on a semi-physical level. NOW, you have to tell a command interpreter what you want, and much gets lost in the interpretation.....
I was working in a computer shop when Windows 3 first came out. The mouse and even the (obviously non-standard) video card didn't fire up until well into the installation process so we learnt to run it all blind and via the keyboard. Idiotic really...
My dad had bought a Timex sinclair 1000 "back in the day". What a bunch of fun that was, though even then, I really hated that keypad. I wrote some neat little things for that - even in 1k. A couple of weeks later we picked up the 16k upgrade module which was as big as my fist.
So that was a DSDD floppy wasn't it. But I'm pretty sure that they capped out a 1.2MB formatted.... I still feel young, at least when I walk into a Walmart...
Are you by any chance talking about the Shugart 901 single sides single density drives that had a little felt pad one one side to maintain pressure between the head and floppy? Then after that the Shugart 850's and 851's came out up to 1M on 8" floppies double sided double density.
Had a stock of new, never used 8" floppies that we had to use at KSC in the terminal controllers. Elephants never forget. I finally tossed them when I moved about 10 years ago.