VOGONS


Missing conventional memory

Topic actions

First post, by Riikcakirds

User metadata
Rank Member
Rank
Member

I have been testing an old motherboard from 1996, a Gigabyte Socket 7 GA586-ATS. Clean installed DOS 6.22 and when I run the mem command, conventional memory shows 631K instead of 640. This is with nothing loaded in config.sys or autoexec.bat, not even himem.sys, just a clean boot. The machine has 8MB EDO ram installed, pci matrox millemium 4mb, and old 2gb hard drive.
In the bios all options are turned off, all Shadow RAM ranges set to off, all com ports, parallel, off etc.
Is there a way I can find out what is using this 9K of conventional memory or free it up to get the full 640k.

Reply 2 of 28, by Riikcakirds

User metadata
Rank Member
Rank
Member
konc wrote on 2020-12-11, 16:42:

Any chance the hard disk has some DDO (Dynamic Drive Overlay) installed?

No DDO, just normal fdisk and format, using fat16. Also I should mention, no sound card, only video card and hard drive connected using pata cable on ide 0 of the onboard motherboard controller (also tried ide 1 connector). Chipset is Intel 430FX. Not using a mouse, only PS2 keyboard connected.

Reply 3 of 28, by OzzFan

User metadata
Rank Newbie
Rank
Newbie

Is that 631K total? Or 631k available? DOS itself needs memory to run, which includes IO.SYS and MSDOS.SYS, as well as the command interpreter. A plain install will not be loading DOS into the HMA, so it must be loaded low into the 640K area. Use MEM /C /P to see a breakdown of what is consuming memory.

A (mostly accurate) listing of my computer systems: http://www.shelteringoak.com/OzzNet/

Reply 4 of 28, by Caluser2000

User metadata
Rank l33t
Rank
l33t

There's no memory missing at all. See ^^^^^^^^^^

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 5 of 28, by Riikcakirds

User metadata
Rank Member
Rank
Member
OzzFan wrote on 2020-12-11, 16:56:

Is that 631K total? Or 631k available? DOS itself needs memory to run, which includes IO.SYS and MSDOS.SYS, as well as the command interpreter. A plain install will not be loading DOS into the HMA, so it must be loaded low into the 640K area. Use MEM /C /P to see a breakdown of what is consuming memory.

Typing in mem, the 'Total' column shows 631K. Every other system I have shows 640K in the total column.
Nothing else is loaded, no himem.sys or anything, but even if it was this would not reduce the total column, and doesn't on my other dos computers.
Is there a utility or dos program that can list what is using this 9K of memory.

Reply 6 of 28, by Jorpho

User metadata
Rank l33t++
Rank
l33t++
Riikcakirds wrote on 2020-12-11, 17:08:

Is there a utility or dos program that can list what is using this 9K of memory.

Did you run mem /c /p as has already been suggested?

If all else fails there are definitely tools that will let you look at raw memory. Debug and MSD are the first ones that come to mind, though there are surely more elegant solutions.

Last edited by Jorpho on 2020-12-11, 17:33. Edited 1 time in total.

Reply 7 of 28, by OzzFan

User metadata
Rank Newbie
Rank
Newbie
Riikcakirds wrote on 2020-12-11, 17:08:
Typing in mem, the 'Total' column shows 631K. Every other system I have shows 640K in the total column. Nothing else is loaded, […]
Show full quote
OzzFan wrote on 2020-12-11, 16:56:

Is that 631K total? Or 631k available? DOS itself needs memory to run, which includes IO.SYS and MSDOS.SYS, as well as the command interpreter. A plain install will not be loading DOS into the HMA, so it must be loaded low into the 640K area. Use MEM /C /P to see a breakdown of what is consuming memory.

Typing in mem, the 'Total' column shows 631K. Every other system I have shows 640K in the total column.
Nothing else is loaded, no himem.sys or anything, but even if it was this would not reduce the total column, and doesn't on my other dos computers.
Is there a utility or dos program that can list what is using this 9K of memory.

So just to be clear, total memory is 631K and available memory is even less than that?

A (mostly accurate) listing of my computer systems: http://www.shelteringoak.com/OzzNet/

Reply 9 of 28, by Riikcakirds

User metadata
Rank Member
Rank
Member

Got back home, it is exactly 632KB of conventional memory, so 8kb is missing, not 9kb.
These are two screenshots, clean boot to DOS, the only thing running is SNARF, dos screen capture tsr that takes up 4K. I used it to take the pictures.

MEM

SNARF000.jpg
Filename
SNARF000.jpg
File size
27.08 KiB
Views
1210 views
File license
Public domain

MEM /C /P

SNARF001.jpg
Filename
SNARF001.jpg
File size
41.29 KiB
Views
1210 views
File license
Public domain

Reply 10 of 28, by OzzFan

User metadata
Rank Newbie
Rank
Newbie

Thank you for providing those screenshots. Run the Microsoft Diagnostics (MSD.EXE) and take a look at the memory map. Does it say anything is using the first 8K or the last 8K in the conventional memory area? Another tool that may be helpful if you can get it is the Quarterdeck Manifest diagnostics program (MFT.EXE), usually included with QEMM386.

[Edited] I'm trying to replicate on my systems and I saw that MSD does not show memory below 640K, though I can confirm MFT does. Netroom Memory Manager's Discover.exe will also show memory below 640k as well.

A (mostly accurate) listing of my computer systems: http://www.shelteringoak.com/OzzNet/

Reply 11 of 28, by darry

User metadata
Rank l33t++
Rank
l33t++

Thank you for the info.
2 questions:
a) Do you have an ISA or PCI disk controller in that machine ?

b) If you create a bootable floppy, copy mem.exe to it and boot from it, do you get the same results?

My guess is that you either have a disk overlay you don't know about, a bootsector virus or some disk controller or other memory mapped device that is taking up that RAM .

Reply 12 of 28, by Riikcakirds

User metadata
Rank Member
Rank
Member
darry wrote on 2020-12-11, 20:38:
Thank you for the info. 2 questions: a) Do you have an ISA or PCI disk controller in that machine ? […]
Show full quote

Thank you for the info.
2 questions:
a) Do you have an ISA or PCI disk controller in that machine ?

b) If you create a bootable floppy, copy mem.exe to it and boot from it, do you get the same results?

My guess is that you either have a disk overlay you don't know about, a bootsector virus or some disk controller or other memory mapped device that is taking up that RAM .

No ISA or PCI disk controller. The only expansion card attached is a Matrox Millenium 4MB PCI VGA card. All other ISA and PCI slots are empty. Also a 2GB ide hard disk connected to the onboard ide controller. Motherboard uses Intel 430fx chipset.

I formatted a 1.44mb floppy and used sys a: Booted from a: with no autoexec.bat or config.sys . Floppy contains only command.com, io.sys, msdos.sys and mem.exe - conventional memory total is the same 632KB.
I have taken the floppy and Hard disk and attached them to my Win10 computer, scanned with Mcafee anti-virus and sophos endpoint command line scan. Checked boot sectors, all clean.

Reply 13 of 28, by darry

User metadata
Rank l33t++
Rank
l33t++

Hmm, this is strange and I am running out of ideas .

Are you running BIOS version 1.32 www.gigabyte.com/au/Motherboard/GA-586A ... support-dl ?

Have tried resetting to default in BIOS setup ?

The only other thing that I can think of is that your video card's BIOS is using 8KB of RAM below the 640KB mark, for some reason . I don't know how plausible that is, but testing with another video card, if possible, might be worth it .

EDIT : Or you have a virus that McAfee and Sophos do not detect . If you have a floppy drive on a modern PC, you could try downloading https://www.ibiblio.org/pub/micro/pc-stuff/fr … /FD12FLOPPY.zip which is a bootable installer floppy companion to the FreeDOS ISO, but you can exit the installer to DOS and run mem.exe . That way, you increase the chance the you are running from an uninfected bootable floppy .

Last edited by darry on 2020-12-12, 00:45. Edited 1 time in total.

Reply 15 of 28, by Riikcakirds

User metadata
Rank Member
Rank
Member
darry wrote on 2020-12-12, 00:37:
Hmm, this is strange and I am running out of ideas . […]
Show full quote

Hmm, this is strange and I am running out of ideas .

Are you running BIOS version 1.32 www.gigabyte.com/au/Motherboard/GA-586A ... support-dl ?

Have tried resetting to default in BIOS setup ?

The only other thing that I can think of is that your video card's BIOS is using 8KB of RAM below the 640KB mark, for some reason . I don't know how plausible that is, but testing with another video card, if possible, might be worth it .

EDIT : Or you have a virus that McAfee and Sophos do not detect . If you have a floppy drive on a modern PC, you could try downloading https://www.ibiblio.org/pub/micro/pc-stuff/fr … /FD12FLOPPY.zip which is a bootable installer floppy companion to the FreeDOS ISO, but you can exit the installer to DOS and run mem.exe . That way, you increase the chance the you are running from an uninfected bootable floppy .

It is running the latest bios, 1.32. I flashed an older bios version but it still shows 632K memory in DOS. Downloaded FD12FLOPPY, booted freedos and shows 632K free memory. To be safe I also booted from an original win98se oem cd , this also shows 632K.
Tried different memory, 16mb edo, no difference, also ran memtest 4.73 overnight and it passed 8 times. The PC has been rock solid in terms of working and I haven't had any stability problems(forgot to mention cpu is a P100).
After searching every option in the bios, I noticed something obvious that I missed before. The first menu screen in the bios, where you can set time and date, shows a summary of the pc's memory in a box near the corner. In that box it shows "BASE MEMORY 640K", so the bios is seeing the full 640K.

Reply 17 of 28, by Riikcakirds

User metadata
Rank Member
Rank
Member
Jorpho wrote on 2020-12-12, 18:41:

The board has a slot for cache RAM, right? Is there anything in that slot?

The coast slot is empty. My revision of the board has the coast slot but also 2x 128KB pipeline burst cache chips soldered to the motherboard.

This picture is the same rev GA-586ATS as my board:
s-l1600.jpg

Reply 18 of 28, by cyclone3d

User metadata
Rank l33t++
Rank
l33t++

When searching on google, I see a 2006 Gateway laptop that only reports 632k conventional RAM.

At this point, I am guessing it is just how that board was designed.

Are you sure there isn't anything in the BIOS that references something to do with 8KB RAM?

Have you tried loading the BIOS defaults?

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 19 of 28, by Riikcakirds

User metadata
Rank Member
Rank
Member

I have loaded the bios defaults, no change. Also reflashed every version of the bios available, from oldest to newest. I have turned off everything in the BIOS, even the floppy. No mention of 8kb or memory regions.

I guess it's just a bit maddening not having the full 640kb. Would be good to know though what is actually using this missing 8KB. I tried Manifest diagnostics program (MFT.EXE), with QEMM386 but it doesn't even list the region from 632 - 640kb.
Can't find Netroom Memory Manager's Discover.exe, It appears Mcafee bought them and updated DOS versions were included in "McAfee Utilities v3.11 & V4 but again difficult to find.
I'm not that experienced with dos and learning as i go, are there any good utils or ways to show what program/rom/software is using conventional memory regions. Even a way in DOS to copy the first megabyte region of memory (0kb - 1024kb) to a file and examine it in a hex editor.