On Fri, 5 Oct 2012, David Riley wrote: If it is convenient to post the model numbers, we can probably identify them. The source/vintage makes tham all probably "1.2M" (anybody who wants to argue the impreciseness of that designation can come up with a CONCISE (not paragraph long) and unambiguous name for that type of drive) If any of them have an asterisk embossed on the front, those are "360K" drives made during the time of "1.2M" drives. The dual drive is presumably "1.2M/1.4M", although other [R at RE] configurations, even 360K/720K did exist. -- Grumpy Ol' Fred cisin at xenosoft.com

On Fri, 5 Oct 2012, Jules Richardson wrote: That is just as good as type 1, 0, 2, 7, etc.! Sure that Kevin won't mind?

On 10/05/2012 10:01 PM, Fred Cisin wrote: I've wondered if those were grandfathered in by non-PC vendors, such as NEC. Anyone try to format a single-density 8" on their APC by way of specifying DRIVPARM? --Chuck

On 10/06/2012 08:53 AM, Fred Cisin wrote: Well, not exactly on the Japanese DOS-V variant of MS-DOS. I suspect that the single-density operations are only valid on DOS-V because the standard PC BIOS interface is very different from that embodied in PC98. If you're talking about double-density, it's easy enough to find out. Well, recall that there was an odd behavior in at least one version of DOS prior to 3.3 that required one to prefix DRIVPARM with a series of 01 (Control-A) characters to be recognized. Was it PC-DOS? I don't recall. --Chuck

5.25", 80 cylinder, 2 head, 360rpm, 500kbps data rate in MFM mode :-) But I wil lagree that '1.2M' is common usage, and pretty unambiguous. Similarly 1.44M for the 500kbps MFM data rate 3.5" drive (I do object to a 'megabyte' being 10^3*2^10 bytes, but it's common usage...) -tony

Perhaps we should just accept that '1.2M' and '1.44M' are names for such drives without tryign to decode them any further. Yes, there may be idiotic reasons for such names, but can we ignoe thaose? I have n problesm with 56Kbuard if used to describe a serial interface running at that bit rate. I dop have a rpblem with it beiing used for the line-side interface of cetain telephoen modems :-) -tony

Excctly. The other idea would eb to use the Teac suffix leters, and call them 'Type G' (and 'Type H' for '1.44M' 3.5" drives. But I susepct that would eb more confusing. -tony

On Fri, 5 Oct 2012, David Riley wrote: Compaq used a variant of these at one time. IIRC, you never want to turn the lever on these without a disk or cardboard insert installed. The small nylon part that pushes the clamper down can easily crack otherwise. Maybe they fixed this in later drives? Other than the lever issue, these were pretty well built and not that hard to service. Typical mass-produced 5.25" of that era and they used a really cheap head actuator motor. Not nearly as easy to service as say a Teac FD-55. The FR-506 was among my least favorite 5.25" drives. These are built like a tank, and like the Teac FD-55, use a full size stepper motor to actuate the heads. If this is the drive I think it is, these were really well built. They had lots of jumper options and the LED plugged into a socket on the front and didn't use a lens so you could swap from amber/green with only having to remove the faceplate. I saw examples of these drives well into the 486 era with the only real difference being the faceplate and LED color. If someone wants to put a blue T1-3/4 LED in a 5.25" drive, this is one of the easier drives to convert. Aka Mitsumi. Mitsumi used a lot of Toshiba parts but from memory these drives tended to be a little better engineered than similar drives from Toshiba. I still have several shelves of 5.25" drives myself and eventually I'm going to need to clean out some of my old inventory too. I have a huge stack of Teac FD-55GFR drives with gray faceplates and green LED lenses that came out of 486 era systems that had 5.25" drives removed to make room for cdrom drives. Is there any demand today for such 1.2MB drives with gray faceplates?