Not seeing enough memory though its there.

[Julian H. Stacey]

I've found the answer to my RAM puzzle: Hardware design limitation.

   - Main board has 32M soldered on,
   - Single slot. (lettering on PCB, 168 pin DIMM 3.3V Unbuffered),
     can take 1 DIMM (though board works without).
   - Plugging in a 32M Ram DIMM, BIOS reports 64 MB.
   - Chips on main board: 
   	1 x SB82437VX System Controller
   	2 x S82438VX Data Path 
   	Intel PCIset 430 VX spec claims to support 4 to 128 M DRAM
   - I guess board implemented as up to 64 M on the DIMM slot & [up to 64M
     in theory, or 32M in practice] soldered on the board. So 96M max.
   - Weirdly, 128 DIMM +32 on board reported as 56, Bad DIMM maybe ?
     (RAMOS Technology Co Ltd RM28S180TC-13AC 128MB, Sync, 133 MHz, CL3.)
   - I have here loose: 32M, 128 & 256. To raise my dmesg from 64 to 96,
     I would need to use a 256M DIMM ! 
   - Time to swap with my other machines (though not sure of speed issues).

   - I also found a probable red herring:
		Some problem with MS @ 64M
		http://h10025.www1.hp.com/ewfrf/wc/softwareDownloadIndex?softwareitem=33937&lc=en&cc=us&lang=en&os=19&product=92286&dlc=en
		Presario Fix for Windows 95 NTKERN Error with 64 MB RAM

		Intended for use on systems with Windows 95 OSR1
		or OSR2. Affects Compaq Presario desktops and
		notebooks with Windows 95 and EXACTLY 64 MB of
		memory (RAM).


Last posting for Ref.:

> Hi Hackers cc Gary J,
> On a Compaq Presario 2254 with 7.0-Release & Generic kernel, I'm
> not seeing enough RAM: A 128M DIM reports as 56M, a 256M reports as
> 96M.  Any ideas please ?
> 
>    dmesg
> 	FreeBSD 7.0-RELEASE #0: Sun Feb 24 19:59:52 UTC 2008
> 	    root at logan.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC
> 	Timecounter "i8254" frequency 1193182 Hz quality 0
> 	CPU: AMD-K6tm w/ multimedia extensions (233.03-MHz 586-class CPU)
> 	  Origin = "AuthenticAMD"  Id = 0x562  Stepping = 2
> 	  Features=0x8001bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8,MMX>
> 	  AMD Features=0x400<<b10>>
> 	real memory  = 100663296 (96 MB)
> 	avail memory = 84484096 (80 MB)
> 	pnpbios: Bad PnP BIOS data checksum		# Dont know why bad
> 
>    With a 128M RAM
> 	Without	hw.physmem= in /boot/loader.conf
> 		dmesg
> 			real memory  = 58720256 (56 MB)
> 			avail memory = 43507712 (41 MB)
> 		sysctl -a | grep mem
> 			hw.physmem: 45572096
> 			hw.usermem: 33267712
> 			hw.realmem: 58720256
> 	With	/boot/loader.conf hw.physmem=134217728
> 		same as above except
> 			hw.usermem: 33312768
>    With a 256 RAM
> 	power on Bios auto resizes to about 96M !
> 	Without	hw.physmem=
> 		dmesg
> 			real memory  = 100663296 (96 MB)
> 			avail memory = 84484096 (80 MB)
> 		sysctl -a | grep mem
> 			hw.physmem: 87515136
> 			hw.usermem: 74280960
> 			hw.realmem: 100663296
> 	With	/boot/loader.conf hw.physmem=268435456
> 		same as above except
> 			hw.usermem: 74141696

Julian
-- 
Julian Stacey: BSDUnixLinux C Prog Admin SysEng Consult Munich www.berklix.com
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