Re: ISA Memory hole at 15-16 MB

From: Erik Mouw (J.A.K.Mouw@its.tudelft.nl)
Date: Thu Aug 03 2000 - 10:54:53 EST


On Thu, 3 Aug 2000 17:34:19 +0530 , Abhishek Khaitan wrote:
> While I was going through the Linux Device Drivers book by Allessandro
> Rubini, I came to know that at the time of 286 computers, ISA memory was
> mapped between 15 and 16MB for RAM. Since at that time nobody had more than
> 1-2 MB of RAM, people had no problems accessing the ISA memory.

More or less correct. Some high-end (well, at that time) video cards could
map their video memory linear at 15-16M.

> But now, as everybody has around 64MB RAM, so when we access that memory
> between 15 and 16MB (the ISA memory hole), are we referring to physical RAM
> or to ISA card's memory?

Physical RAM, although some PCs still allow you to create a memory hole
from 15-16M to accomodate the use of those old ISA video cards.

> Where can I get more details on this?

Your computer's BIOS manual.

Erik

-- 
LART. 250 MIPS under one Watt. Free hardware design files.
http://www.lart.tudelft.nl/

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Mon Aug 07 2000 - 21:00:11 EST