TRS-80 Model 4P memory check

[Junior Ramos]

Hi to all,
Does anybody know how to check, how much memory have my computer?
I have a model 4p with TRSDOS, LDOS, MultiDOS, and some other programs.
In Basic mode when type Print Men jus appears 29974. I check the computer
and appears to have 128k, due all socket are fully with ram chip. I think with CP/M
display the rams, but don't have a copy of CP/M.
Any different between 26-1080 & 26-1080A
Also a Gate Array what mean?
Any help please,
THANKS

 

[leeb]

There is a built-in memory test on the 4p but I do not believe it goes past the usual 64k...
If you hold down the PERIOD key (board or keypad) while powering up, it will show up and ask for ENTER to begin...

IF IT SHOWS YOU ADDRESSES you have memory that is in question...
BASIC uses A BUNCH of ram to run... so 29974 is not unreasonable... as far as I know... when I bring up MBASIC under CP/M it shows 29752... so you're doin' good!

All the memory test programs I have for CP/M do not test the upper bank either... they would have to be specially written to access it...
I actually have some bad ram 'up there' (which came from the lower bank when I bought new) but it is rarely used except for a RAMDISK under CP/M that I almost never use... once I get CPM3 running in banked mode that will have to change...


The Gate Array difference is a change in the way the memory and I/O were accessed... Not a truly big deal as long as it seems to be working okay...
I THINK the 1080a is the first gate array change... but dont quote me on that! :D

Hope this helps!

 

[Junior Ramos]

Thank you

 

[Rick Ethridge]

Your 4P, 1080A, is a green-screen gate array version. It's difficult, short of opening the case, to determine how much memory is installed. There was a program that allows three different programs to operate in LSDOS that required the additional ram. Of course CP/M works creating a drive "M" ramdisk. I finally started using my 4P after a three year hiatus. It still works! I used David Keil's Model III/4 emulator on an Athlon 950 MHz slot A motherboard and a 1.2 meg fdd to create new boot disks. The necessary .dsk files are on the web site http://www.discover-net.net/~dmkeil/trs80/model4.htm. *ADVISORY* LS-DOS 6.3.1 only supports dates to the end of the year. You'll need to patch a copy of 6.2 which supports dates long after we're dead. Do NOT attempt to create boot disks using Win 2000 or higher operating systems! If you require additional assistance just reply here.

 

[billdeg]

Testing 4P's

Testing 4P's

I have four 4P's that I am testing, one has bad RAM.

Here is a screen shot of the RAM program referred to above:

Here are the four systems:

I plan to put at least one of these up for sale, but I'd like to fix the RAM first, it's the unit on the middle left. It's a 26-1080A model with the green monitor text.

Bill