I recently upgraded my big box to 1 Gig of Ram. At boot the screen was blank, but with help and research I restored that by using vga=normal in lilo. From what I could tell from dmesg it said I needed a highmem enabled kernel.
So I follow the steps on the selecting kernel page on the slackware website. (in the book section)
(I can't post the URL here because I haven't posted enough, if someone needs it,please pm me)

when I reboot, it starts loading, but then starts reporting irq conflicts, segmentation faults etc. I can't get to the console to see what dmesg says.
The only thing I changed in make menuconfig is the himem support option, so I don't understand why it's not working.
Thanks in advance.
I'm still working with the old kernel, not the full 1 gig of ram, and no tux at boot.
I miss him.

I assume it's Slackware because you said Slackware in your post?

Are you saying that all of this happened after the only thing you did was add RAM?

I will tell you right now that, unless I'm mistaken, you don't need to do anything to your box with 1GB of RAM. I run 1GB of RAM in my laptop that runs Slackware 9.1 with no problems.

Hmm...

Peace,
Whitehat

Highmem support is for greater then 4GB of RAM (aka over the amount that can be accessed by the original 32bit x86 processors as 2^32 = 4GB).

My best guess is that the new RAM you added is not good.

Whitehat: forgot to mention I'm running slack 8.1
jtshaw: No, did a ram test. Also it works with knoppix live cd, windows 98, windows xp.
Also according to dmesg it's saying only 890 Megs will be used, it requires a himem enabled kernel.

Having the same thing, but I am able to boot.

dmesg output:

Warning only 896MB will be used.
Use a HIGHMEM enabled kernel.
896MB LOWMEM available.

This is after I recompiled my kernel with Himem enabled.

I'm having the same exact issue...linux will only use 896mb. Has anyone found a way to fix this? I just put another 512mb stick in yesterday.

Dmesg >
Warning only 896MB will be used.
Use a HIGHMEM enabled kernel.
896MB LOWMEM available.
On node 0 totalpages: 229376
DMA zone: 4096 pages, LIFO batch:1
Normal zone: 225280 pages, LIFO batch:16
HighMem zone: 0 pages, LIFO batch:1
esterday.

Got it working (finally).

After recompiling the kernel several times with himem enabled, it just worked. Was weird, I would enable himem and compile but it would say it wasn't enabled in the kernel messages.

i use 1.5 gigs and i did have to enable high memory to get it to see over 1 gig

High Mem 4 Gig = 1-4Gig
High Mem 64 Gig = 4-64Gig

-Joey