Date: Sat, 10 May 2008 08:26:41 -0400
From: Allison
Do a A>:ASM BIGFIL.AAB and forget the disk in B:
and you remember
why you hate that.
Or doing "ASM BIGFIL.ASM" or even just "ASM". I got into the habit
of using M80/L80 as soon as I got my hands on a copy. DRI assemblers
(even RMAC) weren't any great shucks.
But then I wa an early adptor of hard disk and from
late '80 on
had at least a 5mb drive to avoid that. Is that less authentic?
By the end of 1981 I'd built a system with romdisk and ramdisk
and no floppy or har disk. Was that authentic?
I think I failed to make my point well enough. Almost all the people
who worked with CP/M initially did so in the context of floppy disks.
Someone attempting to duplicate that experience would get a less-than-
authentic experience without that aspect, in much the same way one
would be deprived of the experience of big mainframe iron without the
machine room noise level. Could you get a true experience of running
OS/360 without a card reader? An authentic experience consists of
all aspects of the experience, not just the convenient or pleasant
ones. Without the whole, one gets a "dude ranch" picture.
What is authentic? To me if the platform has 8080,
8085,
Z80, Z180/64180, Z280, or NSC800 it's running on real iron. Of
course if you have a Z380 or eZ80 in native mode or a NEC V20
in 8080 mode those may count too.
No, one gets extra bugs with a V20 that the 8080 never had.
1.4 really didn't even do a DISK bios, it was
embedded in the bdos.
the bios for 1.4 was only terminal, punch reader and printer IO.
Yes, it ws a pain to interface any new disk to it.
Not according to my archives. While it's true that the 1.4 BIOS
lacked the configurability of 2.0/2.2 (i.e. there were no DPBs, etc.
to define your own disk format), it contained the disk access code
(e.g. SELDSK, SETTRK, etc.) If you'd like, I can send you a copy of
the CBIOS that came with my Tarbell controller, complete with
Processor Technology video board driver (which I didn't use). It's
remarkable in one aspect--it allows for simulated 2-drive operation
on one drive by prompting for the A: or B: floppy when required.
CP/M 1.4 had the right idea--it supported only one diskette format,
so if you had more than 250K of storage, you were pretty much forced
to accommodate this by simulating multiple floppy drives. (Wasn't
there an early system that used an IMI "shoebox" drive for the Apple
II that simulated about 50 floppies?) Where things got out of hand
is when DRI said "Roll your own" with no guidance as to disk format
standards.
It is in 2.0 (deblocking). However their explanation
is thin and
some of the fine details have to be infered by really reading the
code. It was very mysterious when I did it for the first time back
in '80 when I was working with a early sample 765 DD FDC. It was
later that Andy Johnson-Laird wrote The Programmers CP/M Handbook
which covers the subject in much greater detail and has two BIOS
exammples that are very commented.
It's been years since I've chatted with Andy. My acquaintance with
him began after his book, however and I hadn't even realized that
he'd done anything with CP/M.
Cheers,
Chuck