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BlueSCSI HDD Speed ...
Posted by: Arbee on 2024-08-04 13:23:58
None of the 68K systems used DMA except the Quadra AVs so SCSI throughput was capped fairly low.
Posted by: franklyn on 2024-08-08 10:31:56
... a real SCSI Harddisk is a little bit ( 20%) faster than the BlueSCSI with a Sandisk Extreme SD card on my IIsi.
Posted by: eharmon on 2024-08-08 17:22:35
What driver are you using? From my experience any of the later drivers are about the same speed for an SD card, but the early ones are pretty bad, especially the official ones.

Also I have noticed certain access patterns are just kinda slow on Blues/Zulus/etc, and a fast hard disk can still beat them in those cases. If you look at the open pulls, there's some folks who looked at significant improvements to the SD drivers, but unfortunately I think they dropped it before finishing.

They still smoke at random access though, which matters the most for most active use.

Then there's SCSI Manager 4.3 which, contrary to many internet claims, can and is be loaded at boot in 7.5+ for, I think 030+ devices? It can definitely be better in certain cases.
Posted by: franklyn on 2024-08-09 02:57:08
FWB Harddisktoolkit 1.8
Posted by: franklyn on 2024-08-12 04:23:29
i take more tests and the Seagate ST1480N is 20% faster than the BlueSCSI (extreme Sandisk card) on my Macintosh IIsi ...

On a Quadra the BlueSCSI v2 is faster than the Seagate Harddrive ...
Posted by: eharmon on 2024-08-19 22:10:48
Then there's SCSI Manager 4.3 which, contrary to many internet claims, can and is be loaded at boot in 7.5+ for, I think 030+ devices? It can definitely be better in certain cases.
040 devices. TIL17019 says:
SCSI Manager 4.3 adds several new features to the SCSI architecture of the Macintosh. These features include:
• SCSI-2 compliance
• Concurrent asynchronous I/O
• Disconnect and reconnect

SCSI Manager 4.3 is supported on all Power Macintosh, and 68040 Macintosh desktop computers.
...
SCSI Manager 4.3 is part of the ROM in all Power Macintosh and Quadra AV computers. Other 68040 Macintosh computers require the SCSI Manager 4.3 extension
...
Direct memory access is also used by SCSI Manager 4.3. This capability is available on the Quadra 660av, Quadra 840av and all Power Macintosh computers.
Just to close the loop.
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