ISA Memory hole at 15-16 MB

2000-08-03 Thread Abhishek Khaitan 

Hi!

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. 

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?

Where can I get more details on this?

Thanks  Regards,
Abhishek Khaitan

Re: ISA Memory hole at 15-16 MB

2000-08-03 Thread Johannes Niess 

Abhishek Khaitan [EMAIL PROTECTED] writes:

 Hi!
 
 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. 
 
 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?
 
 Where can I get more details on this?

Abhishek,

Nowaday BIOS'es have an option for this. If enabled, your RAM is
reduced to 15 MB. Off is the default value, but I don't know how the
ISA bus is adressed in this mode.

Johannes Nieß