HP Forum Archive 03

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3 1/2 Inch Floppys For HP9121D Message #1 Posted by Fred Ellers on 11 June 2000, 9:15 p.m. In reactivating a HP87XM I am trying to restart a HP9121 dual 3 1/2 inch floppy drive and now find that this was the first application of the Sony 3 1/2 inch drive so the floppys were only formatted for 270 kilobytes. By experiment I have determined that the HP87XM and HP9121 will not initialize either the low density 3 1/2 floppys or any higher density. I have put in an ad for 3 1/2 inch 270KB floppys but have not had, perhaps not suprisingly, a single response. By open case inspection, a low density 3 1/2 inch floppy seems to enter the drive freely, engage and spin OK so the problem seems to be entirely related to magnetic preprogramming to allow the disc to accept the initialize command. Any feedback, particularly from current users of the HP9121, certainly would be appreciated.

Re: 3 1/2 Inch Floppys For HP9121D Message #2 Posted by Steve on 12 June 2000, 9:47 a.m., in response to message #1 by Fred Ellers From memory, these early drives used the same media that was eventually used in 720k drives. The early drives were single sided. I have an HP-IL drive of similar vintage (the drive looks the same to me) and these use 720k disks without any trouble. The 9121 is HP-IB, and has blue eject buttons from memory? Watch out. The lubricant on these old drives dries up, and this can result in damage to the heads during disk ejection.

Re: 3 1/2 Inch Floppys For HP9121D Message #3 Posted by Fred Ellers on 13 June 2000, 1:39 a.m., in response to message #2 by Steve Steve Many thanks for your comments. You remember the HP9121 correctly in that the power button is blue and the control is via HP-IB. So far I have not been able to get the HP87XM to initialize a 3 1/2 inch disc in the HP9121 but I do have an operable 5 1/4 HP82901M that works OK. I have tried some low density 3 1/2 inch discs in the HP9121 and that does not work ie unable to initialize. I note the HP87 manual does not use a FORMAT command and have thought that may have been reserved for a low level ie factory format of the 3 1/2 inch discs but that is just a wild guess. As I bone up on the initial Sony development of the 3 1/2 drive it seems the HP87 was the first use of this drive and disc outside of Sony and the new discs had the tracks (particularly the first track) and the radial start point already recorded and if these were not where they were supposed to be the disc would not initialize. Per your suggestion I will see what I can do about drive lubrication. Thanks again for your suggestions-so far this has been harder than I thought it would be to add the HP9121. Fred

Re: 3 1/2 Inch Floppys For HP9121D Message #4 Posted by Steve on 17 June 2000, 4:06 a.m., in response to message #3 by Fred Ellers Have you tried finding owners of any HP150 computers? These used these drives, and owners of them may be able to point you in the right direction. And thinking back... I know somewhere that was using touchscreen HP150s until fairly recently (less than 5 years ago). I'll enquire there for you. They don't have a lot of technical information (or didn't) but they might have manuals... (and yes, they were the OLD model HP150s, the HP150A series).

Re: 3 1/2 Inch Floppys For HP9121D Message #5 Posted by Andrés C. Rodríguez on 17 June 2000, 9:20 a.m., in response to message #3 by Fred Ellers One of the first adopters of 3 1/2 floppies was the first Macintosh computers, recording 400 KBy on each floppy. However, they used a constant linear velocity (or should I call it "variable angular velocity"?), so the formatting is clever but very incompatible with every other use. If the floppies were pre-formatted at the factory, then you should only look for HP sites. If there is any way to format the floppies (other than the factory), then many Macintosh, Amiga, Data General One (laptop), Toshiba T1000 (laptop), and MSX machines used "low" density floppies in the 1980s; and you may found some floppies on these environments... Oh, there were strange things those days, specially in 5 1/4 floppies: double heads on the Apple Lisa, hard sector formatting, with a hole for each sector and a 3 hole index mark ...

Re: 3 1/2 Inch Floppys For HP9121D Message #6 Posted by Wayne Brown on 18 June 2000, 11:07 a.m., in response to message #5 by Andrés C. Rodríguez Commodore's 5 1/4" disk drives did something similar to Apple's constant linear velocity trick. Instead of varying the speed of the motor, they varied the rate at which data was written, writing faster on the outer tracks than on the inner ones. The result was the same as Apple's: larger disk capacities and complete incompatibility with anybody else's drives (including Apple's). This was especially frustrating to those of us with the Commodore 64's Z80 coprocessor and CP/M option. It would run lots of the CP/M programs available, but couldn't read any of the commonly available CP/M disk formats. Unless you had a modem or wanted to do a lot of typing, you were out of luck. Thank goodness for the RCP/M bulletin boards, because they had tons of stuff to download that would run on any CP/M system (including my 64). I still remember how exciting it was when my favorite RCP/M BBS (Northstar/Downey in Downey, CA) got a gigantic 10 MEGABYTE hard drive! Wow, we thought no one would EVER write THAT much software. :-)

Re: 3 1/2 Inch Floppys For HP9121D Message #7 Posted by Steve on 18 June 2000, 6:57 p.m., in response to message #6 by Wayne Brown The Sirius 1 (AKA Victor 9000) also had variable speed drives. The hum changed as the motor speed varied. There was a program that played "Mary had a little lamb" on the drives :-) It could put 600K per side on what were effectively 360K disks -- remembering that 360K disks were DOUBLE SIDED. Mind you, it payed to use the slightly better disks, and I was paying up to $US5 per disk... Oh, and there was a 5Mb hard disk -- and it cost about 20% more than the computer. It really makes the price of HP gear (that I was using at the time) look fairly reasonable. They were only about twice the price :-)

Re: 3 1/2 Inch Floppys For HP9121D Message #8 Posted by Jan H. Bos on 20 June 2000, 8:18 a.m., in response to message #1 by Fred Ellers Reading the Q's and A's again about this subject, I am just wondering about the capacity of the 9121 drives. As I ordered my HP 86B system in Switzerland in 1984, it was originally ordered with 5 1/4 drives, but delivered with a HP 9121 drive, because it was new and gave more storage capacity. I have in mind that the capacity was about 360 k per floppy, but I will check in the manuals and build up the stored 86b system again. Jan

Re: 3 1/2 Inch Floppys For HP9121D Message #9 Posted by Edgar Valle on 2 July 2000, 4:04 p.m., in response to message #1 by Fred Ellers Fred, I have my hp87 working with 9121D, and also with my hp86B with no problem. my 9121D can "INTITIALIZE" (1.44M)floppies but they will be "Formated" to 270k. I think your 9121 is Bad.

Re: 3 1/2 Inch Floppys For HP9121D Message #10 Posted by Fred Ellers on 7 July 2000, 9:08 p.m., in response to message #9 by Edgar Valle Edgar Many thanks for your observation and I think you read the situation correctly in that the 3 1/2 inch floppy is bad. Anyway I am contributing the entire setup to an Australian museum as the best thing to do since the 5 1/2 floppy is working OK Regards, Fred

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