J.Pearce@ucl-cs.UUCP (12/13/89)
From: J.Pearce@uk.ac.ucl.cs As I have been lead to understand the built-in video interface on the MacIIci uses bank A memory, but the Memory Decode Unit allows you to use non-contiguous memory. So is it possible to move half the memory in a 4M system to bank B, to reduce the performance degradation due to video lock-out? John R. Pearce. jpearce@uk.ac.ucl.cs Computer Science Department, University College London, Gower Street, London, WC1E 6BT, ENGLAND.
levin@bbn.com (Joel B Levin) (12/14/89)
In article <483@ucl-cs.UUCP> J.Pearce@ucl-cs.UUCP writes: |As I have been lead to understand the built-in video interface |on the MacIIci uses bank A memory, but the Memory Decode Unit |allows you to use non-contiguous memory. So is it possible to |move half the memory in a 4M system to bank B, to reduce the |performance degradation due to video lock-out? Unfortunately, this would leave you with every other WORD (two bytes), which is a little more noncontiguous than the engineers had in mind :-). You need to set up SIMMs four-at-a-time because each SIMM contains memory for eight bits of the thirty-two bit memory width for the entire 4MB (or 1MB for 256KB SIMMs). /JBL = Nets: levin@bbn.com | "There were sweetheart roses on Yancey Wilmerding's or {...}!bbn!levin | bureau that morning. Wide-eyed and distraught, she POTS: (617)873-3463 | stood with all her faculties rooted to the floor."