27 Aug
2005
27 Aug
'05
2:40 p.m.
From: "Allison" <ajp166 at
bellatlantic.net>
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
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.
Other implmentations from V2 on it was easily to store
the BIOS in ROM and use that to boot the system.
This is for a writing project, so I'd like
to get it right,
Thanks!
Brian
Thre is much myth, and misinformation of old cpm. Much of
it was from people that had never used or never been there
(in time) and their sense of reference is the PC rather
than what came before.
Allison
27 Aug
27 Aug
3:13 p.m.
what machine and/or controller was this that had no ROM at all? I
never have dealt with any system that at least didn't have some type
of startup code somewhere other than a disk drive. DMA would need to
be setup unless it was hardwired. The original Intel Intellec-8
required that you enter a program jump into memory that pointed to
the program monitor. Intel didn't call it a BIOS though.
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
30 Aug
30 Aug
3:23 a.m.
At 02:40 PM 8/27/05 -0700, Dwight wrote:
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
<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
From:
"Allison" <ajp166 at bellatlantic.net>
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
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.
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