1 Jun
1999
1 Jun
'99
8:33 a.m.
Don Maslin <donm(a)cts.com> wrote:
On Fri, 28 May 1999, Dwight Elvey wrote:
Dwight,
My next question is, could someone send me an
image of a
directory that I could use to build my disk?
--snip-- Here is an image of a 2.2 directory from an
8"SSSD disk. Hope it proves
useful. (It is not Imsai.)
Hi Don
Thanks a lot. As it was, I didn't need to do anything to start
the directory. If it had the original E5's in it, CPM thinks
it is an empty disk. Clever of DR, wasn't it! I'm learning
more about CPM than most people know anyway.
I was able to get a the system to the "A>" late Monday
night. I then transfered some files by my simple serial
downloader into the memory and used the SAVE command
to write them to files. I did this for the DUMP, ED,
STAT and ASM commands. DUMP and STAT seem to work
OK but I'm having troubles with ED and haven't tried
ASM yet.
The ED command has some serious troubles. It allows me to
do "I" and "T" commands but won't do a "L" or
"E" commands correctly.
Saving text to a file is one of the most useful parts of
an editor but being able to move around is number 2 or 3.
Since DUMP works, I'll use that to read back what the file
has in it. If not that, I'll make an image file for CCP, BDOS
and CBIOS. I'll then be able to tell where the problem
lies.
I've had some issues with RAM loosing data but I not sure
where the problem is yet. This may be my problem. The
RAM boards I have are some older 4K, 8K and one 16K
static RAM boards that make up the needed 64K ( actually
62K ) by the CPM.SYS file I have.
I have some DRAM boards that I've used with my Poly88.
These are 64K boards and I thought I'd use them but the disk's
DMA doesn't seem to write to them. I'm able to read and write
from the front toggles, just not from the DMA to the
RAM.
Does anyone know what the problem is here? Is there some
timing or pin out issue with DRAMs that would cause this
to happen in a standard IMSAI 8080? I'd really like to use
this DRAM because I trust it more than the statics in the
system, at least until I get things fully functional.
In any case, I think just getting to the A> prompt is
a major mile stone. I had to completely write a boot loader,
CBIOS, disk formatter and serial data transfer to get this far.
My longest to trouble shot problem was the difference
between JNC and JC used with SUB.
Dwight
1 Jun
1 Jun
8:54 a.m.
I've had some issues with RAM loosing data but I
not sure
where the problem is yet. This may be my problem. The
RAM boards I have are some older 4K, 8K and one 16K
static RAM boards that make up the needed 64K ( actually
62K ) by the CPM.SYS file I have.
If static ram is loosing data you likely have a bus noise or other timing
problem. If your running a 4mhz z80 try running with 1 waitstate on
memory accesses, some of those old boards didn't do 4MHz. If your running
an 8080 many of the dram card didn't work well with oder 8080 designs.
Some like the Vector 48k, will not run at all as they require ta z80 for
correct refresh..
Does anyone know what the problem is here? Is there
some
timing or pin out issue with DRAMs that would cause this
to happen in a standard IMSAI 8080? I'd really like to use
this DRAM because I trust it more than the statics in the
system, at least until I get things fully functional.
For those old systems DRAM was the lest reliable generally and most
statics tended to work ok. DMA... you sure that card is a DMA, very few
were. Most of the older systems were totally incompatable to barely
compatable with DMA devices and bus termination for those is a must have.
In any case, I think just getting to the A> prompt
is
a major mile stone. I had to completely write a boot loader,
CBIOS, disk formatter and serial data transfer to get this far.
yes it is. You have some basic hardware reliability issues to deal with
yet and likely bus noise is one of them. The IMSAI was far better than
the Altair but like most of the older s100 crates terminating the bus was
not a bad thing and sometimes required for reliable operation.
Allison
9:11 a.m.
allisonp(a)world.std.com wrote:
--snip--
If your running
an 8080 many of the dram card didn't work well with oder 8080 designs.
Some like the Vector 48k, will not run at all as they require ta z80 for
correct refresh..
These are DRAM boards of two types that I've had working with my
Poly88 that is a 8080 system ( some mods on the CPU card to get refresh
to work ). The IMSAI has the original 8080 processor board.
They seem to hold data fine so it looks like the
refresh isn't the issue. Since the data isn't modified at
all by the DMA, I'd think it was a missing WR strobe or
not getting the address there at the right time.
--snip--
For those old systems DRAM was the lest reliable
generally and most
statics tended to work ok. DMA... you sure that card is a DMA, very few
were. Most of the older systems were totally incompatable to barely
compatable with DMA devices and bus termination for those is a must have.
I tend to agree here but in this case, I have 4 ea 8K, 4 ea 4K
and one 16K static cards. I can replace this with one 64K card
if I get the DMA write and read to work correctly. As I said,
these cards are old and I've already had failures with less than
20 hours of trying to bring it back up.
--snip--
You have some basic hardware reliability issues to
deal with
yet and likely bus noise is one of them. The IMSAI was far better than
the Altair but like most of the older s100 crates terminating the bus was
not a bad thing and sometimes required for reliable operation.
It has a terminator card in it. Since this also has voltage
regulators on it, it might even be a source of problems as well.
I'll loke at it as well.
Dwight
9337
days inactive
9337
days old
2 comments
2 participants
participants (2)
-
allisonp＠world.std.com -
elvey＠hal.com