steve@violet.berkeley.edu (Steve Goldfield) (02/15/90)
I recently obtained a IIci for my boss. I ordered a video card, thinking I had to have one as with my Mac II. When it arrived, I was told that I didn't have to have it because there was built-in video capability on the mother board but that the machine would run about 15 percent faster if I had an external video card because it would remove the video load from the mother board processor and memory. If so, that would appear to be a simpler solution to speeding up the IIci than to have to juggle programs and their memory allocations to get them to run in a particular bank Steve Goldfield
folta@tove.umd.edu (Wayne Folta) (02/16/90)
>... If so, that would appear >to be a simpler solution to speeding up the IIci than to >have to juggle programs and their memory allocations to get >them to run in a particular bank Having to juggle around programs is a pain. But the advantage over a seperate video card is three-fold: 1) it saves you several hundred dollars (you paid for the built-in video...); 2) the internal video is measurably faster than a video card, since it avoids going through the NuBus; and 3) it leaves three slots free. -- Wayne Folta (folta@cs.umd.edu 128.8.128.8)
rory@fps.com (Thomas (Rory) Bolt) (02/16/90)
One interesting thing to note is that the physical memory map of the IIci is NOT contiguous. If you get into MacsBug 6.1 and type "TM" to display the MMU registers and take the time to decode the page table entries, you will find that the MMU will map virtual addresses in the range 0 to 4 Mbytes to the bank B RAM if you have 8 Mbytes installed. This would tend to suggest that you would actually want to load your programs into LOW memory for maximum execution efficiency. As a side issue, since the upper half of the 8 Mbyte space is actually mapped to bank A RAM, references to the stack & possibly the heap MAY be the culprits! I have not gathered enough evidence to give a definitive answer to the question of how best to load programs in the IIci. Rory Bolt