CS MKIII Maxtransfer

[Amigaz]

Out of curiiousity I went thru the filesystem/partiton config on my A4000/CS MKIII/OS3.9 machine running a real SCSI hdd on the SCSI bus on the CS MKIII.
I am using the PFS3 filesystem, version 18.5. I set up this system over 15 years ago and have forgot what motivated me to put the current values for maxtransfer, blocksize and buffers.

I have maxtransfer set to 0X00FFFFFF, is that the correct value for this hardware/filesystem setup?

[Boing-ball]

Out of curiiousity I went thru the filesystem/partiton config on my A4000/CS MKIII/OS3.9 machine running a real SCSI hdd on the SCSI bus on the CS MKIII.
I am using the PFS3 filesystem, version 18.5. I set up this system over 15 years ago and have forgot what motivated me to put the current values for maxtransfer, blocksize and buffers.

I have maxtransfer set to 0X00FFFFFF, is that the correct value for this hardware/filesystem setup?

I believe so.

Have you checked the settings on the SCSI ROM? I.e hold down ESC key on power up? 

[Amigaz]

I believe so.

Have you checked the settings on the SCSI ROM? I.e hold down ESC key on power up?

You mean these settings?

[Boing-ball]

You mean these settings?

Yes. I take it you have setup the ID of the HDD to be “Synchron” etc..? As that will speed up things.

Also worth getting the Phase 5 SCSI software tools and 8 stall them on Workbench as well…

[Amigaz]

Yes. I take it you have setup the ID of the HDD to be “Synchron” etc..? As that will speed up things.

Also worth getting the Phase 5 SCSI software tools and 8 stall them on Workbench as well…

Yes but I am very satisfied with the speeds I am getting (circa 30mb/s)
I want to be positive that I am using the correct maxtransfer file system setting for my setup.

[Boing-ball]

Yes but I am very satisfied with the speeds I am getting (circa 30mb/s)
I want to be positive that I am using the correct maxtransfer file system setting for my setup.

Yes as far as I am aware. Best person to answer this is Thomas. The guy is a guru when it comes to this stuff.

I know with CF and SD card 0x01fe00 is favoured on IDE back in the day. But these days on OS 3.2 HDToolbox it’s default for maxTransfer is what you are using now.
If you do start to get data corruption. Then check PFs3 version isn’t 18.5 as it’s known for corrupting data on small file transfers.
And if that doesn’t work, then try 0x01fe00, but this will slow down transfers.

Toni Willen has a link to a BETA version 20.0. Which I have been using without any major issues. This allows for 4096K block transfers, which the current 19.2 doesn’t do, even if set in HDToolbox.

[Thomas]

MAXTRANSFER IS NOT A SPEED LIMIT!!!!!!!!!!!!

It is a transfer unit size limit. It splits larger transfers into multiple smaller ones. The overhead is marginal. It does not reduce speed.

Also it is not a matter of "back in the day" versus "these days". It is solely a matter of the capabilities of the used hardware and software components.

3.2 claims not to have a MaxTransfer issue any more, but this is only true for the built-in scsi.device.

AFAIK SCSI has a two byte length field in most commands. Therefore with 512 byte blocks the theoretical max transfer unit is 32 MB, i.e. the MaxTransfer value would be 0x2000000. But any properly programmed driver would not need a MaxTransfer reduction. Just use 0xFFFFFFFF.

However, it you use an IDE component on the SCSI bus, for example by a SCSI-IDE converter or a flash card reader, you should be careful. Various firmwares might not properly translate SCSI commands (with two bytes length) into IDE commands (one byte length).

It does not hurt to set the well known 0x1fe00 always and everywhere.

[Boing-ball]

MAXTRANSFER IS NOT A SPEED LIMIT!!!!!!!!!!!!

It is a transfer unit size limit. It splits larger transfers into multiple smaller ones. The overhead is marginal. It does not reduce speed.

Also it is not a matter of "back in the day" versus "these days". It is solely a matter of the capabilities of the used hardware and software components.

3.2 claims not to have a MaxTransfer issue any more, but this is only true for the built-in scsi.device.

AFAIK SCSI has a two byte length field in most commands. Therefore with 512 byte blocks the theoretical max transfer unit is 32 MB, i.e. the MaxTransfer value would be 0x2000000. But any properly programmed driver would not need a MaxTransfer reduction. Just use 0xFFFFFFFF.

However, it you use an IDE component on the SCSI bus, for example by a SCSI-IDE converter or a flash card reader, you should be careful. Various firmwares might not properly translate SCSI commands (with two bytes length) into IDE commands (one byte length).

It does not hurt to set the well known 0x1fe00 always and everywhere.

Everyday is a school day. Thanks Thomas 👍🏻

[Amigaz]

MAXTRANSFER IS NOT A SPEED LIMIT!!!!!!!!!!!!

It is a transfer unit size limit. It splits larger transfers into multiple smaller ones. The overhead is marginal. It does not reduce speed.

Also it is not a matter of "back in the day" versus "these days". It is solely a matter of the capabilities of the used hardware and software components.

3.2 claims not to have a MaxTransfer issue any more, but this is only true for the built-in scsi.device.

AFAIK SCSI has a two byte length field in most commands. Therefore with 512 byte blocks the theoretical max transfer unit is 32 MB, i.e. the MaxTransfer value would be 0x2000000. But any properly programmed driver would not need a MaxTransfer reduction. Just use 0xFFFFFFFF.

However, it you use an IDE component on the SCSI bus, for example by a SCSI-IDE converter or a flash card reader, you should be careful. Various firmwares might not properly translate SCSI commands (with two bytes length) into IDE commands (one byte length).

It does not hurt to set the well known 0x1fe00 always and everywhere.

Thanks, I am glad to see a familiar face here from when I was active here in the past. Since then I have lost alot of knowledge when it comes to these things.
At the moment I am slowly reviving my old Amiga's that have been kept in storage for over 15 years.
I will take this advice and put it into practice.