How to check the memory of it doesn’t show you how at startup

[abruno17]

My Compaq portable came with a really weird board that not only has a serial board, but it has several banks of chips that I can only guess are ram. So since I know my Compaq was configured with 256k I want to see how much if any ram this board adds. What command do I type to check the memory? I’ve tried several that was suggested and I was told it was invalid command. So what should I try? And before anyone asks no the computer does not tell me how much ram at startup. It’s just a line ‘counting’ how much ram there is.

 

[mbbrutman]

Does the board have DIP switches? If there is RAM for the system it has to be mapped into the address space, i.e.: assigned an address. And it has to be adjacent to existing memory so that you have one large contiguous block of memory.

If you have the switches set incorrectly, you get a "hole" in the memory. The computer tries walk through all of the memory and as soon as it encounters and address that does not respond correctly (a hole), it stops the count. This might be happening to you.

 

[krebizfan]

Chkdsk with early DOS versions will report the amount of memory DOS sees. MEM does the same in DOS 5 and later.

Note that some serial port cards had their own memory and even a processor. Examples of that were used for logging scientific instruments. If unsure, post an image of the card and possibly someone will recognize what it does.

 

[sergey]

My Compaq portable came with a really weird board that not only has a serial board, but it has several banks of chips that I can only guess are ram. So since I know my Compaq was configured with 256k I want to see how much if any ram this board adds. What command do I type to check the memory? I’ve tried several that was suggested and I was told it was invalid command. So what should I try? And before anyone asks no the computer does not tell me how much ram at startup. It’s just a line ‘counting’ how much ram there is.

Could be an AST SixPakPlus board or similar. As mentioned above, ideally you find what is the configuration of the board - its memory should be configured start right after the on-board memory ends

 

[hard_fault]

Chances are, the number of contiguous 1k memory blocks found at startup is stored in the BIOS data area at 0040:0013 [WORD].

If you run DOS DEBUG and type "d 0040:0013" and look at the first 2 bytes it returns, it should tell you how much RAM the BIOS found.

For example, on my Tandy 1000 TL, I get:
0040:0013: __ __ __ 80 02 .. .. ..

The BIOS in my machine found 0x0280 (hex) contiguous 1k blocks of RAM (640 KB).

Note: Contiguous memory does not include video memory or extended RAM. So it doesn't see the 128 kB video memory upgrade in my Tandy 1000 TL.

 

[abruno17]

Update so I figured it out. Well, my hunch was right, it is a serial board/memory board. It’s weird, it doesn't have a brand name as far as I can tell, I’ll take it out and get a picture of it but it is made in Japan and it had a battery that I had to replace. But it does add 384k for a total of 640k. Perfect because I wanted to run Sim City. Now there could be more ram on there I dunno. But I’m like I said, mystery solved.

 

[hard_fault]

I've got one of those big ol' 16-bit ISA RAM boards in my Packard Bell PB286 AT clone. Could not find the documentation listing the DIP switches anywhere.

Had to brute-force trial and error the DIP switch settings. Eventually got it to detect 2048 KB in the entire system, which means it's only providing 1408 KB from the card. I know the card has a full 2K on it, but I was sick of fooling with it at that point so I just accepted that amount of RAM.

Perhaps one day I'll pull it out and actually figure out the DIP switch settings by tracing out the circuit.

 

[abruno17]

I've got one of those big ol' 16-bit ISA RAM boards in my Packard Bell PB286 AT clone. Could not find the documentation listing the DIP switches anywhere.

Had to brute-force trial and error the DIP switch settings. Eventually got it to detect 2048 KB in the entire system, which means it's only providing 1408 KB from the card. I know the card has a full 2K on it, but I was sick of fooling with it at that point so I just accepted that amount of RAM.

Perhaps one day I'll pull it out and actually figure out the DIP switch settings by tracing out the circuit.

Mine doesn’t have have dip switches just jumpers. And like I said it’s also a serial card. I’m using it mainly as a mouse interface. I mean what else can you really do with serial on a Compaq Portable.