Falcon + Bluescsi - Image size tests

[whomper]

Hi,

With all the Falcon and SCSI testing flying around, I wanted to test my bluescsi in various configurations.

As in Bluescsi every image file on SD card is a SCSI device, I am limited to 6 drives and I'm getting roughly 1770 K/s with 11 ms access time.
Note: you need to make sure your image file is not fragmented as otherwise expect to get roughly 40 ms access time.

I thought to myself, why wouldn't I create 4 GB image files and partition that down to 4 partitions in HDutils. used the standard TOS partition and could copy large files around. However, I noticed slowness in some of the partitions.

Partition 1 performed as it should, about 1770 K/s but access time rose to 40ms. With every partition that follows, read dropped by about 50 K/s and access time doubled or more. My last partition (4) has a Tx rate of about 1500 K/s and access time of about 300 ms.

It might be how bluescsi implemented the SCSI protocol with respect to how it works with a physical image that is logically partitioned, but to be the only practical bluescsi setup is one image file per partition.

[Steve]

This is the kind of thing you probably should report to the bluescsi github issues:
https://github.com/BlueSCSI/BlueSCSI-v2/issues

But it's also possible it could have something to do with Atari partitioning.

[whomper]

Thanks, I just posted there.

I'm not sure its the HD driver as I have a CF IDE of 4GB partitioned to 4 1GB ones and it performs great.

[don_apple]

Since there are multiple different BlueSCSI models (v1, v2, external (DB25), internal (desktop), Pico , Pico 2, ...) which have different performance, it would be helpful if you could provide some more information which exact model you use.

And also which BlueSCSI firmware and which settings you use in the bluescsi.ini, since this could also have an influence on the performance.

Also, how are you measuring the transfer rate and the access time?

And last but not least, which hard disk driver (HDDRIVER, AHDI, ...) are you using?

[whomper]

More info:

1. Bluescsi External DB25.
2. Bluescsi firmware - Not sure as it's not in the log file. Its either latest or just one before.
3. bluescsi.ini - SelectionDelay=0
4. Tx rate measured by both Xferrate and AHPT94.PRG, access time measured via AHPT94.PRG
5. HDDriver used, 12.71 and 12.72 tested.

[don_apple]

2. Bluescsi firmware - Not sure as it's not in the log file. Its either latest or just one before.

The firmware version actually appears on the second line of the log.txt:

Code: Select all

Platform: BlueSCSI (Pico1/W)
FW Version: 2025.08.02-rel Aug  2 2025 16:25:01     <===

[whomper]

I've reinstalled the latest firmware, formatted a new SD card, created a fresh 4 GB image and copied it to the SD card using Terminal and validated that I am getting no fragmentation in the logs.

I've then partitioned it to 4 1GB images in Atari and run all tests afresh.

I am now not getting any of the previously seen behavior. Not sure what it was related to but it seems I can work with large and partitioned Image files.

Not sure why I got those issues in previous setup and tests, but running everything afresh produces good results.

This enables me to have the max number of logical drives while using 3 SCSI IDs on the bus.

[don_apple]

OK, good to know that it works now.

I tried to reproduce your test results using a ZuluSCSI Pico on my DFB1X-equipped Falcon (using HDDriver 12.72), but wasn't able to. Since the ZuluSCSI Pico is very similar to the BlueSCSIv2 DB25 I originally was surprised that I could not reproduce your initial results.

But since you now can't reproduce them either it confirms that the SCSI-support on both the BlueSCSI and the ZuluSCSI works as it should.

How did you create the 4GB disk image btw. ? This might have had something to do with the initial issues.

[whomper]

I used Disk Jockey on OSX and its BlueSCSI setting.
My guess is .IMG (or .HDA) file fragmentation might be the cause of this. It is important to make sure there are non and that should be validated by observing the bluescsi log o the SD card.It does not hamper Tx rate as much as has it does access time.