MaxTransfer rate for SATA?

Does anybody know what the correct MaxTransfer rate is for SATA drives?

Mine was set to some crazy large default, I've changed it to IDE standard (128K/$1FE00) but not sure that is right?

The mask was some weird default too.. so I've changed that to 32-bit aligned. Does anybody know if it matters or makes any difference whether the mask is for all memory or 32-bit aligned only?

The max transfer is not a rate setting, it is a maximum-block-in-one-go setting. All modern drives can handle any block size. Only some obscure early '90s disks had problems with blocks larger than 128k. The driver then had to split up transfers in 128k blocks. This is not an issue anymore as far as I know. Just set it to 0x7FFFFFFF.

Since IDE is 16-bit 16-bit alignment was probably a good idea for PATA disks. The PCI bus is 32-bit though so maybe 32-bit alignment would be better. However, enforcing too large alignment may have performance issues as well since the driver then needs to realign unaligned blocks which may take extra time and may not be needed.

SATA is serial and therefore 1-bit. However, the PCI-bus is still 32-bit. I really have no idea what alignment will be best performance-wise. I would actually assume that it is irrelevant for SATA disks.

There shouldn't be any need to change the default values. Only badly written drivers need adjustments in MaxTransfer and Mask.

@Chris
$1FE00 will hurt performance.

Mine were all set to maximum, however they were the opposite way round to what MediaToolBox says they should be (MaxTransfer was 7FFFFFFF, whereas the drop-down says Mask should be that, etc), which is why I was concerned.

I've changed them all now to MediaToolbox's suggested maximums.

I tried a ssd hd in my sam440ep. I used the default values and got pretty ok speed tests compared to other os4 systems.

When I had a large (3.5") SATA HD in my Sam440, I recall getting around 100MB/sec in tests. I guess SSD might be even faster? (Although the main benefit of SSD is minimal "seek" delay.)

@chrisH

The best test result for scsispeed thread at aw.net.....


Sam440ep @667mhz
Dev type : Corsair CSSD-F60GB2
Remov Dev : no
Remov Med : no (probably harddisk)
Tot. Size : 60022480896 bytes, 58615 mbytes, 58 gbytes

6.Progs:Scsispeed4> scsispeed DRIVE sii3114ide.device:0 FAST BUF1=8192 BUF2=16384 BUF3=32768 BUF4=65536
MKSoft ScsiSpeed 4.2 Copyright © 1989-92 MKSoft Development
AmigaOS4 port by Stéphane Guillard
------------------------------------------------------------
CPU: 68020 AmigaOS Version: 53.12
Device: sii3114ide.device:0


Testing with a 8192 byte, MEMF_FAST, LONG-aligned buffer.
Read from SCSI: 64903577 bytes/sec

Testing with a 16384 byte, MEMF_FAST, LONG-aligned buffer.
Read from SCSI: 87642112 bytes/sec

Testing with a 32768 byte, MEMF_FAST, LONG-aligned buffer.
Read from SCSI: 105306521 bytes/sec

Testing with a 65536 byte, MEMF_FAST, LONG-aligned buffer.
Read from SCSI: 116948992 bytes/sec