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I was wrong, the "bigram" file had no executable flag.
Anyway, even flashed with the commands you mentioned (bigram addmem maprom) the performance of the A2091 is disastrous 110 Bytes/Sec.
If I remove the Bigram2630 the read performance returns to 2Mb/Sec.
I also tried to put the old kickstart 3.1 and the old operating system 3.1. Same thing !
My configuration is:
A2630 + BigRam 2630, A2091 scsi controller. Ace2b 2MB Chip Indivision.
What can I do ?
you are right, however with the command bigram addmem maprom the machine crashes.
If I do maprom addmem, on the other hand, everything is OK.
The GuruROM will use non-DMA transfer, which is a lot faster than using DMA through chipmem - that's what the original 2091 ROM defaults to, if no memory in Z2 area is available.
The order or options should not play a role at all. Maybe something else changed with the feature changes?
Actually, GuruROM v6 will use the following priority for DMA transfer buffers (with CPU copy-up) when one is needed for transferring data to/from targets >16MB Zorro II address spaces:
- Allocate a 16K buffer in FastRAM pool which has the 24-bit DMA attribute.
- Allocate a 16K buffer in ChipRAM pool which always has the 24-bit DMA attribute (but subject to Agnus taking bus priority, so slower).
- PIO - This option will never apply to any A2000-based use case. Mentioned for completeness only.
This prioritization will get tripped up by the C0.0000 remap tricks (as noted in the thread), as native C0.0000 memory range is normally tagged with the 24-bit DMA attribute. The driver also assumes all target addresses <16MB are natively 24-bit DMA-accessible in an A2000.
The last reply was more than 365 days ago, this thread is most likely obsolete. It is recommended to create a new thread instead.
