HP 9114B drive question (Hey Joe!)

From: Joe <rigdonj_at_cfl.rr.com>
Date: Wed Mar 27 19:50:02 2002

At 09:52 PM 3/27/02 +0000, you wrote:
>> SOME of HP 3.5" drives would support high density 1.44mb disk but the
>> 9114 would not. In fact, I haven't been able to get the 9114 to work at
>> all with any 1.44Mb disks. They might work if they were bulk erased
>> first, I haven't tried that. But standar d 720k disks work fine in them.
>> I've found the same to be true in the 9121 and several other HP 3.5"
>The 9114A, 9121, 9122 (not C, I guess), 9123, 9133, etc use a full-height
>Sony disk mechanism. This one will not work with HD disks because the
>disk-inserted sensor (a spring-loaded flag and a slotted optoswitch on
>the motor PCB) lines up with the density select hole on the HD disk. The
>result is that the drive thinks no disk is inserted.

   I've never looked the internals of the drive but that certainly makes sense since the error message returned says that there is no media in the drive.

>I've not tried covering the hole in an HD disk so the sensor is
>triggered. Some people have, and report it works 'sometimes'. But I stick
>to real 720K disks...

   Ditto! I tried covering the hole but it didn't work for me.

>> drives. In fact, IIRC the 9122 C (emphasize C) is the only drive that I'll
>> found that will use the 1.44mb disks.
>> The capacity of the disk is dependent on the machine it's being used
>> with and what optional parameters that you give the Format (or Initialize)
>> command. It's generally about 710k but on the HP-41 it's only about 270k
>> due to the small size of the 41 m emory and limited disk DIR, FAT
>> (actually LIF) and other disk info that the 41 can hold.
>The HP41 is intersting. When the 82160 HPIL module ROM was written, the
>_only_ mass storage device was the 82161 cassette drive with a capacity
>of 128K. Moreover, the 82161 does not respond to the 'extra' DDL/DDT
>commands that the 9114 responds to that cause the latter to report the
>capacity. So the HP41 assumes that all mass storage devices are 128K (512
>'blocks') long.
>If you use a 9114 drive with an HP41, then it'll report 'MDM FULL' (or
>whatever the medium full message is) when you try to put more than 128K
>on the disk. _Unless_ you manage to artificially create a file that spans
>the 128K boundary, when it seems to work properly. There's an HP program
>for this, and a modified verison in PPC journal. It uses the Extended I/O
>ROM to send DDL and DDT commands to the 9114 to create such a file. I've
>not bothered -- 128K on a single disk is still plenty of space for an HP41...

   128K is a HUGE space for a HP 41! The 41 only has 2.2k of RAM!

Received on Wed Mar 27 2002 - 19:50:02 GMT

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