Bringing up a CPM

From: Chuck McManis <cmcmanis_at_mcmanis.com>
Date: Thu May 27 14:48:54 1999

Its definitely up to the bios, when I wrote the BIOS for the Cromemco 16FDC
I ran out of space, so I took advantage of the fact that a) I could write
full tracks and b) that most SD disks could handle DD and wrote the first
two tracks of the disk double density, even if the disk was "formatted" for
single density. (I also wrote the formatter (in Turbo PASCAL no less!))

--Chuck

At 03:17 PM 5/27/99 -0400, you wrote:
>
>On Thu, 27 May 1999, Dwight Elvey wrote:
>>
>> 1. Are the directory sectors interleaved like the file sectors are?
>
>The boot sectors (reserved tracks) are generally not, the rest of the disk
>is. CPM it self does not care it's a BIOS issue..
>
>> 2. When I checked the size of the CPM image that was on the
>> unoffical CPM site, it was 60 sectors in size. When I looked
>> at the manual, it said that this would be loaded by a boot
>> loader that would load in locations 3400H to 4D80H. This is
>> only 51 sectors. This also matches the remaining track
>> zero plus track 1 of a single density disk. What am I suppose
>> to do?
>
>
>
>that means the saved image has either dead space at the end or a bios
>there. It could be that teh file was off a system with 4k allcoation
>blocks so fine sized tend to round up.
>
>The standard size for cpm a is:
>
> CCP 800h 2048 bytes
> Bdos E00h 3584 bytes
> BIOS variable 8"sssd example is 1500bytes.
>
>This is generally stuffed on to the sssd 8" as the first two tracks of the
>disk, 52 sectors total or 6656 bytes for all three components.
>
>Allison
>
>
Received on Thu May 27 1999 - 14:48:54 BST