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How do I see how much memory in DOS?

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mattm16

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Jan 19, 2024
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In DOS 6.22, how do I tell how much RAM is installed? The memory chips do not have the amount on them (they are 72 PIN SIMMs).
 
Try the MEM command.

The chips on each SIMM should have the type printed on them. Adding the values would provide the total for the SIMM.
 
You don't even need to do that in DOS. Every single PC in this world since the XT will show the amount of installed memory during POST. You can also enter the BIOS to see it.
 
On the chips themselves, the only thing on them is the following: 411Y KM41C1000CJ-7. There are 9 chips on the stick, the top one has the following: KT531000 AJ-60 9426. On the stick itself, it states VT-4MX9A.
Does that mean 4Mb? I tried the MEM command and it states Conventional, Upper, Reserved and Extended. These are actually 30 PIN SIMMS I think.
 
Timo W. said:
You don't even need to do that in DOS. Every single PC in this world since the XT will show the amount of installed memory during POST. You can also enter the BIOS to see it.
Click to expand...
If I enter the BIOS, it shows Base Memory of 640K, and Extended as 1024KB.
 
mattm16 said:
On the chips themselves, the only thing on them is the following: 411Y KM41C1000CJ-7. There are 9 chips on the stick, the top one has the following: KT531000 AJ-60 9426. On the stick itself, it states VT-4MX9A.
Does that mean 4Mb? I tried the MEM command and it states Conventional, Upper, Reserved and Extended. These are actually 30 PIN SIMMS I think.
Click to expand...
The references I can find for that label indicate that the chip is a 1 Mbit chip so the whole SIMM should have 1 MB. If you have two SIMMs, the MEM value of 640K base and 1024k of extended would be correct. The remaining 384K is presumably shadowing the memory region between 640K and 1024K.
 
I have 3 chips installed, and it still shows base of 640k, and 1024k extended; however; I can change that number per the manual. Should that number be changed to 2048k?

Now looking at the manual, it states that it comes with either 2MB or 4MB Onboard memory, then you upgrade the memory. So, if it has 2MB onboard, is it not "seeing" the sticks? Or do I have to modify the extended memory field to 4096? In the manual, it shows "onboard" as 2MB, then in the banks they are empty, then you have 2MB total, extended 1MB. If you added 4 - 1MB sticks, the total would be 6MB, with 5MB Extended.

On Board, the memory chips have the following on it: HY534256J-70 and there are 20 of them. Would that be 4MB onboard?
 
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mattm16 said:
On Board, the memory chips have the following on it: HY534256J-70 and there are 20 of them. Would that be 4MB onboard?
Click to expand...
The datasheet I turned up for that says those are 256kx4 chips. So a bank of 9 would be 1 MB with a second bank of 9 for a second MB and the other 2 chips presumably giving 256KB to the motherboard video. Yes, it would seem that somehow the system isn't identifying all the memory installed.

What motherboard is it? Double check the SIMMs are seated correctly. Does the motherboard require multiple SIMMs in a bank?
 
A 286 or 386sx would need pairs of 30 pin SIMMs. A 386dx would need multiples of 4.
 
krebizfan said:
The datasheet I turned up for that says those are 256kx4 chips. So a bank of 9 would be 1 MB with a second bank of 9 for a second MB and the other 2 chips presumably giving 256KB to the motherboard video. Yes, it would seem that somehow the system isn't identifying all the memory installed.
Click to expand...

Looking at the OP's older posts I'm going to take a wild guess that the PC in question here is a Packard Bell 610 486 computer. (It would probably be very helpful if they would provide this information when they create posts asking technical questions.)

Banks of 9 Xx4 bit chips would be sort of weird. I guess in theory you could store parity that way, but your RAM controller would have to do "interesting" things whenever there was a byte, 16-bit-word, or non-aligned 32 bit write? Google's failing to find any sort of useful manual for this machine, but there is a picture of the guts of a Packard Bell 610 in this thread here, and the arrangement of the memory banks suggest to me that the system is using 16 of them for 2MB of soldered onboard memory *without parity*. Meanwhile I'm guessing the other four are providing 512K for the onboard video chipset, with the four open sockets over them there to allow expansion to 1MB.

(FWIW, I just found a clearer picture of the motherboard in a Vogon's thread, and it confirms that the chip adjacent to the four chip/socket rows is the VGA chip, and the datasheet for said OAK OTI-77 confirms that this would be a valid RAM configuration for it.)

Anyway. With this information I would expect it would be reasonable for the BIOS to say this motherboard has 640K conventional and 1MB of Extended RAM; I had a 486 based on the same (or at least similar) OPTI chipset as this board, and it could *only* use the 384K between conventional and extended RAM for BIOS shadowing.

mattm16 said:
I have 3 chips installed, and it still shows base of 640k, and 1024k extended; however; I can change that number per the manual. Should that number be changed to 2048k?

Now looking at the manual, it states that it comes with either 2MB or 4MB Onboard memory, then you upgrade the memory. So, if it has 2MB onboard, is it not "seeing" the sticks? Or do I have to modify the extended memory field to 4096? In the manual, it shows "onboard" as 2MB, then in the banks they are empty, then you have 2MB total, extended 1MB. If you added 4 - 1MB sticks, the total would be 6MB, with 5MB Extended.
Click to expand...

And here is your problem, right here. Three SIMMs is not a valid configuration. A 486 computer needs 32 bit wide memory, 30 pin SIMMS are 8 bits wide. (not counting the parity bit) So having three SIMMs installed looks the same as not having any expansion RAM at all. Find a fourth matching SIMM. (Or buy four matching SIMMs. The board *probably* accepts them in up to 4Mb, for 18Mb, but *may* also accept 16Mb SIMMs for up to 66Mb. No idea what those are going for these days.)
 
Eudimorphodon said:
Looking at the OP's older posts I'm going to take a wild guess that the PC in question here is a Packard Bell 610 486 computer. (It would probably be very helpful if they would provide this information when they create posts asking technical questions.)

Banks of 9 Xx4 bit chips would be sort of weird. I guess in theory you could store parity that way, but your RAM controller would have to do "interesting" things whenever there was a byte, 16-bit-word, or non-aligned 32 bit write? Google's failing to find any sort of useful manual for this machine, but there is a picture of the guts of a Packard Bell 610 in this thread here, and the arrangement of the memory banks suggest to me that the system is using 16 of them for 2MB of soldered onboard memory *without parity*. Meanwhile I'm guessing the other four are providing 512K for the onboard video chipset, with the four open sockets over them there to allow expansion to 1MB.

(FWIW, I just found a clearer picture of the motherboard in a Vogon's thread, and it confirms that the chip adjacent to the four chip/socket rows is the VGA chip, and the datasheet for said OAK OTI-77 confirms that this would be a valid RAM configuration for it.)

Anyway. With this information I would expect it would be reasonable for the BIOS to say this motherboard has 640K conventional and 1MB of Extended RAM; I had a 486 based on the same (or at least similar) OPTI chipset as this board, and it could *only* use the 384K between conventional and extended RAM for BIOS shadowing.



And here is your problem, right here. Three SIMMs is not a valid configuration. A 486 computer needs 32 bit wide memory, 30 pin SIMMS are 8 bits wide. (not counting the parity bit) So having three SIMMs installed looks the same as not having any expansion RAM at all. Find a fourth matching SIMM. (Or buy four matching SIMMs. The board *probably* accepts them in up to 4Mb, for 18Mb, but *may* also accept 16Mb SIMMs for up to 66Mb. No idea what those are going for these days.)
Click to expand...
I apologize for not mentioning the PC make/model with this question. It is a Packard Bell Legend 610 486PC. So essentially, this PC has 2MB RAM. So, I do have to use 4 sticks, I cannot use, say 2 sticks? I can use (according to the manual) up to a 4MB chip for a total of 18MB RAM.
 
Thanks everyone. I have ordered 4 - 4mb sticks to max out RAM. You can also add video RAM but i think it would be better to get a video card
 
Do all 386 boards accept 4MB SIMMs?

Asking for myself, for a motherboard I can't find doc on.
CHIPSet CS82310, with the marketing name PEAK/DM.
 
wrljet said:
Do all 386 boards accept 4MB SIMMs?

Asking for myself, for a motherboard I can't find doc on.
CHIPSet CS82310, with the marketing name PEAK/DM.
Click to expand...
No. Some do; many don't. Even for those that do, some were picky as to the type of 4MB SIMM that could be used.

http://www.bitsavers.org/components...MK82310-PI_Super_Technical_Reference_1991.pdf looks like the generic manual for the PEAK/DM. I don't seen anything that would help figure out which 4Mbx9 SIMM would be best.
 
Did you verify that your PB400 2mb motherboard has a 82C495B1 AT U77 chip? If it has a 82C495 AT U77 it is limited to 6mb of ram. Had to return a bunch of 4mb 30 pin SIMMs and get (4) 1mb 30 pin SIMMs to finally get mine working. Mine had the 82C495 ... now I'm trying to decide if I'm happy enough with 6mb of ram or do I try to find a working PB400 with 4mb onboard.

Ram I am using is 1mb 9 chip 70ns 30 pin SIMMs x 4

Added 256k of cache which did speed it up a bit and I've ordered video ram for it as well.

Also added a 2gb CF card for the hard drive and I'm using XT-IDE bios on a NIC to make the CF card work.

Also if you attempt to replace the power supply with an ATX one and an adapter the onboard video card requires -5v so it won't work without a work around.

Figured I would share all my gotchas with my 610 ... hopefully some are useful.opti_82c495.jpg
 
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krebizfan said:
No. Some do; many don't. Even for those that do, some were picky as to the type of 4MB SIMM that could be used.

http://www.bitsavers.org/components...MK82310-PI_Super_Technical_Reference_1991.pdf looks like the generic manual for the PEAK/DM. I don't seen anything that would help figure out which 4Mbx9 SIMM would be
Click to expand...

therrixxe said:
Did you verify that your PB400 2mb motherboard has a 82C495B1 AT U77 chip? If it has a 82C495 AT U77 it is limited to 6mb of ram. Had to return a bunch of 4mb 30 pin SIMMs and get (4) 1mb 30 pin SIMMs to finally get mine working. Mine had the 82C495 ... now I'm trying to decide if I'm happy enough with 6mb of ram or do I try to find a working PB400 with 4mb onboard.

Ram I am using is 1mb 9 chip 70ns 30 pin SIMMs x 4

Added 256k of cache which did speed it up a bit and I've ordered video ram for it as well.

Also added a 2gb CF card for the hard drive and I'm using XT-IDE bios on a NIC to make the CF card work.

Also if you attempt to replace the power supply with an ATX one and an adapter the onboard video card requires -5v so it won't work without a work around.

Figured I would share all my gotchas with my 610 ... hopefully some are useful.View attachment 1271917
Click to expand...
I was going by the manual that said the max was 4mb chips. It has a 82C392 and a 82C495 Chip on the motherboard. The power supply I put in is an AT Power Supply.
 
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