9885 disc on 9825 machine - getting closer


Jack Rubin
 

A recent trip to Los Angeles resulted in a working 9885M drive and so I got back to work on the disk initialization project. The current version of Ansgar Kueckes' HPDir program allows you to create a 9885 disk on a 9895 drive with the incantation 'hpdir -initialize -9885 -s 9825 <msus>'. Once I realized that Ansgar's syntax added an extra zero to the msus (e.g. with my 9895 addressed as 7, the first drive is 7070: and the second drive is 7071:), I was able to [apparently] initialize a disk for my 9885 drive. 

The 'apparently' part came when I hooked the 9885 drive up to my 9825A with the 98217A Disk ROM in place and attempted to access the drive. I heard contacts close and open in the drive cabinet as I powered the 9825 up and down but any attempt to use disk commands resulted in an 'error 03' - mnemonic unknown - on the 9825 console.

Is this a Catch-22? Do I still need the Disk System Cartridge (tape) to 'boot' the disk subsystem before new disk related commands become active? Or is it possible that my ROM is not being accessed?

Thanks,

Jack


 

On Apr 16, 2017, at 21:07, Jack Rubin <j@ckrubin.us> wrote:
Is this a Catch-22? Do I still need the Disk System Cartridge (tape) to 'boot' the disk subsystem before new disk related commands become active? Or is it possible that my ROM is not being accessed?
The 98217 ROM only has enough smarts to boot the binary programs written into the system area on the disk, and probably provides I/O utility routines to drive the interface. Those binary programs are swapped into memory as needed to perform various disk operations. If the floppy was initialized properly with the binary programs in the correct locations. It should work.


Ansgar
 

Hi Jack,

first of all good you have a working 9885!

Sounds as if the system sectors have not been properly initialized. The HPDir function you mention is experimental (means not yet approved). What I did with HPDir is take the system sectors of a known good 9825 disc, keep the sector data permanently into HPDir, and write the sectors during initialization in single sided mode with the 9895 to the floppy, so that it can be read from a 9825 with a 9885. You should be able to use a DD disc instead of an SD disc if you like in case no SD is at hand. Unfortunately I have no 9825 to test on my own, but I will re-check whether the sectors really look like they should with a 9885. I assume that it should not make a difference whether using a 9825A or 9825B, but I am no expert on this.

The msus parameter should be ok with 707: when initializing the disc in the 9895 (no unit specifier needed, if you omit the unit, it should default to 0), otherwise that can be considered as a bug. I'll also check this on my side.

Ansgar


Ansgar
 

Small correction: meant you can use a DS disc instead of an SS disc :-)

I let you know about the checks on my side.

-Ansgar


Jack Rubin
 

Ansgar - re the msus syntax, I don't think it's a bug - it's a feature that you allow more granular addressing, but it wasn't something I was familiar with on my older equipment. I started testing with an HP-85 and talked to the 9895 using msus :770 and :771. When I switched to HPDir, 770: didn't work but 707: did. That's when I realized you had added another addressing digit (that reflects 9845 usage?), thus 7070: and 7071:.

- re DS vs SS disc/k (even HP goes back and forth on "disk" and "disc" spelling) - I've got the covers back on both drives but can the 9885 read both types? There are index LEDs for both disk types in the 9895 but not sure about the 9885.

Craig and others - two questions - first, if I understand your answer, a properly initialized disk should load with the 98217 ROM only and does not require any use of the tape?

- maybe more fundamental, how do I determine if my ROM is in place and actually working? Again, the system test tape seems to be non-existent but I thought that typing reserved words such as 'drive' or 'cat' should get a D or F error rather than an 03 error. More generally, how do I determine if any ROM is in place and functional? Does typing a reserved word work as a quick functional test?

Thanks,

Jack


Paul Berger
 

On 2017-04-17 9:17 AM, Jack Rubin wrote:

Ansgar - re the msus syntax, I don't think it's a bug - it's a feature that you allow more granular addressing, but it wasn't something I was familiar with on my older equipment. I started testing with an HP-85 and talked to the 9895 using msus :770 and :771. When I switched to HPDir, 770: didn't work but 707: did. That's when I realized you had added another addressing digit (that reflects 9845 usage?), thus 7070: and 7071:.
No the 9835/45 use a unique format like nearly every other HP system, it makes it fun switching between them. They use a letter to designate the drive type F=9885 H=9895, the first drive of a 9895 attached to a HPIB adapter with select code 7 and controller address of 7 would be ":H7,7,0" There are also short forms, for instance ":H" = ":H7,0,0"

- re DS vs SS disc/k (even HP goes back and forth on "disk" and "disc" spelling) - I've got the covers back on both drives but can the 9885 read both types? There are index LEDs for both disk types in the 9895 but not sure about the 9885.
The 9885 drive only has the one index sensor and is positioned for single sided media, the drive does however write the data in a double density format.

Craig and others - two questions - first, if I understand your answer, a properly initialized disk should load with the 98217 ROM only and does not require any use of the tape?
The tape utility was only required to write the boot straps onto the diskette, a "properly formatted" diskette for use with the 98217 ROM would need to include these bootstrap, the 98228A ROM does not require these bootstraps to be present. There is a image of the 98228 ROM and suggested electronics available in the file section for this group.

- maybe more fundamental, how do I determine if my ROM is in place and actually working? Again, the system test tape seems to be non-existent but I thought that typing reserved words such as 'drive' or 'cat' should get a D or F error rather than an 03 error. More generally, how do I determine if any ROM is in place and functional? Does typing a reserved word work as a quick functional test?
If the ROM is correctly installed and functional you should get an error other than 3. Beware of the 98218A ROM they have been sold on eBay as the diskette ROM for 9825 but they are really for 9831 (9825A hardware running BASIC) and will not work with the 9825 HPL OS.

Paul.


Paul Berger
 



On 2017-04-17 3:20 AM, Ansgar wrote:

Hi Jack,

first of all good you have a working 9885!

Sounds as if the system sectors have not been properly initialized. The HPDir function you mention is experimental (means not yet approved). What I did with HPDir is take the system sectors of a known good 9825 disc, keep the sector data permanently into HPDir, and write the sectors during initialization in single sided mode with the 9895 to the floppy, so that it can be read from a 9825 with a 9885. You should be able to use a DD disc instead of an SD disc if you like in case no SD is at hand.

The 9885 cannot use double sided media, the drives in the 9885 only have one index sensor and it is positioned for single sided media.

Unfortunately I have no 9825 to test on my own, but I will re-check whether the sectors really look like they should with a 9885. I assume that it should not make a difference whether using a 9825A or 9825B, but I am no expert on this.

It would not make any difference.

The msus parameter should be ok with 707: when initializing the disc in the 9895 (no unit specifier needed, if you omit the unit, it should default to 0), otherwise that can be considered as a bug. I'll also check this on my side.

Ansgar



 

If you haven’t seen it, the 9825DiscProgramming-09825-90220-98pages-Aug80.pdf document contains good information about the binary programs needed on a 9885 disc, where they are placed and what they are used for.