Bit of CP/M trivia needed - test-drb@ccmp.vtda.org

30 Aug 2005

...
 From: "Joe R." <rigdonj at cfl.rr.com>

At 02:40 PM 8/27/05 -0700, Dwight wrote:
  From:
"Allison" <ajp166 at bellatlantic.net>

Subject: Bit of CP/M trivia needed
   From: "Brian Knittel" <brian at quarterbyte.com>
   Date: Sat, 27 Aug 2005 00:58:01 -0700
     To: cctalk at classiccmp.org

Hi all,

Does anybody out there know for certain when the 
term BIOS was coined? I believe it was Gary Kildall,
and from what I can find, it was around 1978 that
he abstracted the I/O and localized it in what
he called the BIOS. Anyone know differently? 
The term BIOS is older, early '77.  It came into use with 
V1.3 I think and for cetertain in V1.4.

 Also -- was the BIOS stored on the CP/M 
floppy, or was it in ROM/EPROM? If not, how
did CP/M machines boot? Was there a dedicated
boot ROM that was used just for startup, and
then the BIOS took over? I had one back in
the day, but I sure can't remember this detail. 
The easy answer is yes.  Tranditional CP/M systems the 
CCP/BDOS and BIOS were on the first two reserved tracks 
of the floppy (8" SSSD) and those were loaded by a boot 
rom. 
Hi
 My understanding was that the first ones had no ROM
and used a DMA controller that loaded bootstrapping
code from the first sector on reset. I have such a
controller on my machine. All RAM, no ROMs.
Dwight

    I don't think so. CPM was first written by Gary Kidall for the Intel
MDS-800 (go read the CPM docs) and they NEVER had DMA capability. They used
a 2k bit bootstrap loaded in a 1702 EPROM. Here is a picture of a MDS-800
with THE actual 1702 Boot EPROM 
Hi
 Yes, what I meant to say was for the S-100. I was told that the first
S-100 implementation used this type of board. I knew Gary used a
MDS-800.
Dwight

...

<http://www.classiccmp.org/hp/mds-800/frnt-pan.jpg>. The 1702 is mapped
into and out of the memory space by the BOOT switch on the MDS front panel.
Allison's description is dead on. Dave Mabry is the expert of the Intel MDS
and he can provide more details about how they're booted and the BIOS table
is loaded. FWIW Gary had a contract to write PL/M for Intel and wrote CPM
as a file handling system for use in developing PL/M. He offered Intel CPM
but they didn't want it since they were working on their own OS.(BIG
Mistake!) Intel's OS was released as ISIS and was only used in the Intel
MDS systems (although I've heard they did have a PC version for a PC based
MDS). ISIS is very crude compared to CPM.

   MDS 800  <http://www.classiccmp.org/hp/mds-800/mds-800.htm>

   You might also want to take a look at 'CP/M and a brief history lesson'
here;  <http://www.classiccmp.org/hp/mds/mds.htm>. I used to have the exact
quotes from Gary but unfortunately the link to them is now dead.

   Joe

   Joe