jperkins@hawk.ulowell.edu (Whatsup?) (03/12/89)
when my AT clone boots up, I see it test memory normally then it tests it in protected mode. What is protected mode, and how can I use it. Thanks in advance -jperkins@hawk.ulowell.edu
tchu@bbn.com (Tom Chu) (03/12/89)
In article <12155@swan.ulowell.edu> jperkins@hawk.ulowell.edu (Whatsup?) writes: >when my AT clone boots up, I see it test memory normally then it tests it in >protected mode. What is protected mode, and how can I use it. > >Thanks in advance > >-jperkins@hawk.ulowell.edu Protected mode in the 80286 mode is a mode of the 80286 that will allow you to address up to up to 16 Megabytes of physical memory. The memory management system of the 80286 also comes into play among other things. In the protected mode a real operating system is needed to take advantage of the 80286 power. This operating system right now goes under the name of OS/2. If you want all the details, you can look up the info in the AT reference manual and an 80286 manual to really understand protected mode operation. All PC-ATs basically run in real mode, and makes a 286 look like an 8086. This was done by IBM so that the PC-AT would be compatible with its daddy, the original IBM PC. T. Chu
daveb@sunybcs.uucp (Dave Borkowski) (06/21/89)
I would like to get some thoughts on getting at memory above 1M.
I need to be able to shuffle around blocks of memory while controlling a
DT 2861 frame grabber. The problem is that frame store memory (4M) has to
be dealt with in protected mode. The only way to get maximum speed out of
this thing is to roll your own. They do provide support (IRIS) libraries
but at best, three frames/sec. I would like to create composite frames built
from sub frames in real time. I believe this is possible if done in protected
mode.
Up till now all that I have seen available is a book by Brumm & Brumm. I leaves
alot of unanswered questions.
Has anyone any experience to share ???
Thanks
Daveb