Re: [Thinkpad] 600X display problem Win98SE

Dr. Jeffrey Race [Sun, Aug 17, 2003 at 11:43:51PM +0700]:
> Now I have the PCMCIA slots working. Next problem: some software won't
> install because the display is 16 colors.
>
> When I go to the display option in Control Panel, it reads:
>
> Laptop Display Panel (1024x768) on Standard PCI Graphics Adapter (VGA)
>
> I am offered two color depth options, 2 and 16.
>
> What is wrong please, and what is the fix? And how did it get to be
> this way? (Result of installing from 600E recovery disk again?)

Computers store information internally using bits, bytes, words and such.

One bit can be either 0 or 1 - that's 2 possible values. Two values. One or
zero. Binary system.

2 bits can be 00, 01, 10, 11 in binary - that's 0, 1, 2 and 3 in decimal,
which gives you 4 possible values.

3 bits can be 000, 001, 010, 011, 100, 101, 110, 111. 8 different values,
ranging from 0 to 7.

To encode [x] colors you need [x] possibilities to save their values. Thus:

  0.5 byte = 4 bits = 16 different numbers
    1 byte = 8 bits = 256 different numbers
    1 word = 2 bytes = 16 bits = 65536 different numbers
    
  Generally 2^n gives you the answer to ,,How much different values can I
  write using n bits''.
    
Now, the practical part:

  1024x768x0.5 = 393216 bytes of video card RAM are needed to use 1024x768
  in 16 colours (4-bit colour depth)
  
  800x600x1 = 480000 bytes of video RAM needed to use 800x600 with 256 colours
  (8-bit colour depth)
  
  800x600x2 = 960000 bytes of video RAM needed to use 800x600 with 64K colours.
  (16-bit colour).
  
  The term ,,colour depth'' is often also named ,,bpp'' (bits per pixel).
  
Divide byte values by 1024 to know, how much kilobytes is this. Divide them
by 1024*1024 - that will give you number in megabytes.

So, you either have too small video RAM to use 1024x768 in color depth
bigger than 4 bits (16 colors), or you have invalid video card driver
installed. Anyway, as you restored from a proper rescude disk, I suppose,
that the driver can be all right, but I'd check it, if it's properly
installed anyway.

I guess the solution seems obvious now, doesn't it?

Regards,

-- 
mp
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