I dug up a pile of Xenix disks in DART format that were imaged in 1991 and they all have the format byte set as Lisa.--
My understanding is that this format byte is stored in each sector header on the disk in GCR (before decoding). Maybe it would be a good idea to check this? One way would be using Copy ][ Mac to look at the sector header pre-decode.
How does BLU record this format byte? Does it copy it from the sector header, or does it guess based on the observed disk format?It's also possible that DC42 on a Mac handles this wrong.
David
On Sun, Jan 21, 2018 at 10:34 AM, Ray Arachelian <ray@arachelian.com> wrote:
On 01/21/18 09:36, Al Kossow wrote:
> On 1/20/18 10:35 PM, David Ryskalczyk wrote:
>> Not being clear there — the Lisa disk images on BitSavers are all
>> DC42, so I’d expect them to have a format byte of 0x12 (DC42) or 0x2
>> (DART); not 0x02 (DC42) or 0x1 (DART, but there are no DART images).
>
> I'll see if I can whip something up to check the values at 0x51 in
> every DC42 I've archived and see what I come up with.
>
Here you go: gcc check-dc42-format-byte.c:
----------- >8 cut here 8< ---------------
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
for (int i=1; i<argc; i++)
{
FILE *f;
unsigned char c;
f=fopen(argv[i],"rb");
if (!f) {fprintf(stderr,"Could not open %s ",argv[i]); perror("\n"); }
else
{
fseek(f,0x51,SEEK_SET);
c=fgetc(f);
printf("%s format byte @0x51: %02x\n",argv[i],c);
fclose(f);
}
}
}
----------- >8 cut here 8< ---------------
compile as usual: gcc check-dc42-format-byte.c -o check-dc42-format-byte
And sample output on some images off bitsavers
$ check-dc42-format-byte *.dc42
682-0073-A_Pascal_2.0_1_cpy1.dc42 format byte @0x51: 02
682-0073-A_Pascal_2.0_1_cpy2.dc42 format byte @0x51: 02
682-0074-A_Pascal_2.0_2_cpy1.dc42 format byte @0x51: 02
682-0075-A_Pascal_2.0_3_cpy1.dc42 format byte @0x51: 02
682-0075-A_Pascal_2.0_3_cpy2.dc42 format byte @0x51: 02
682-0076-A_Pascal_2.0_4_cpy1.dc42 format byte @0x51: 02
682-0076-A_Pascal_2.0_4_cpy2.dc42 format byte @0x51: 02
682-0077-A_Pascal_2.0_5_cpy1.dc42 format byte @0x51: 02
682-0077-A_Pascal_2.0_5_cpy2.dc42 format byte @0x51: 02
mac_supp_1.dc42 format byte @0x51: 02
mac_supp_2.dc42 format byte @0x51: 02
mac_supp_3.dc42 format byte @0x51: 02
ws2.0_1.dc42 format byte @0x51: 02
ws2.0_2.dc42 format byte @0x51: 02
ws2.0_3.dc42 format byte @0x51: 02
ws2.0_4.dc42 format byte @0x51: 02
label_list_for_7_7.dc42 format byte @0x51: 02
lisa_calendar_for_7_7.dc42 format byte @0x51: 02
lisa_macnosy2.55.dc42 format byte @0x51: 02
lisa_phone_book_for_7_7.dc42 format byte @0x51: 02
twiggy$ check-dc42-format-byte *.dc42
t001_Office_System_I.dc42 format byte @0x51: 01
t004_Smalltalk-80.dc42 format byte @0x51: 01
t008_Office_System_II.dc42 format byte @0x51: 01
t021_Lisa_Draw.dc42 format byte @0x51: 01
t025_Lisa_Guide.dc42 format byte @0x51: 01
t044_Lisa_Project.dc42 format byte @0x51: 01
t046_Lisa_Write.dc42 format byte @0x51: 01
t058_Lisa_Graph.dc42 format byte @0x51: 01
BTW: any reason bitsavers doesn't have Lisa Office System 3.x and apps?
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