Low transfer rate on Mega ST4 with UltraSatan

[tnt23]

Hi all,

 

I've finally got my Ultrasatan up and running with my Mega ST4 and TOS 1.02, and decided to go for HDD adapted games. Tried a few with intermittent success, and then discovered that ICD driver is not supported with Gamex.

So I have gladly switched to PP driver as it offers DOS&TOS support for big partitions apart from Gamex compatibility. I am also pleased to say that the support from Peter was extremely quick and friendly. Partitioning and formatting the same SD card, and installing PP driver on it was a breeze. My Mega ST4 boots happily and sees new partitions just fine. And it is very convenient to have disk C as big as 255MBytes, seen from my Ubuntu PC without a hitch.

I have started filling the disk with software. Brought a few ZIP archives to be unpacked with STZIP, however unpacking took seemingly longer than it was with ICD setup. At some point STZIP crashed with rather peculiar message, which unfortunately I did not care to capture. Thought I'd first copy a good 80M of game archives, which I did, and then the system froze while listing files in disk C. Hmmm.

Long story short, I have decided to see just how fast Ultrasatan was. Using AHPT94.PRG utility I have measured both the Hardware and Logical access transfers, which turned out to be ~186 KBytes/s. The access time for Logical drive was around 50ms which I guess is not at all that fast.

Any clues as to what could be the reason for low transfer rates? I've tried a smaller SD card, partitioned again as 255M for Disk C of type C16, it did perform roughly the same.

[ParanoidLittleMan]

There is something bad for sure. UltraSatan should have at least some 800 KB/sec transfer rate.

Most problems are with low quality SD cards, from not trusted sources, although main problem is unreliable write and data corruption with them, by my experience.

It could be problem with Mega ST self, it's ACSI port, DMA chip, or UltraSatan self (not much likely) .

Best would be to try it with some other Atari ST(E) . Honestly, never heard about so low transfer rate with UltraSatan.

[tnt23]

This particular card is an old Nokia 512M microSD, it was not dramatically fast but showed ~500Kbytes/sec:

 

 

Another card is modern 4GB microSD from unknown manufacturer, I'll try to set it up with ICD to measure transfer rate.

 

With my previous ICD setup, I had C disk of 15M and then D of 255M.

Currently my C disk is 'C16' type 255M, and then there's a bunch of 255M disks from D to N. I believe with PP driver C disk can be up to 255M (TOS 1.02 in my case), could this be the problem?

 

Edited December 2, 2019 by tnt23

[ParanoidLittleMan]

Partition sizes have nothing with transfer speed. The reason why C can be up to 255 MB is because max partition size with TOS 1.02 is 256 MB. So, why not have C with that ? Older drivers have somehow simplified driver code read from C, after hard disk autoboot, and that's the reason for that 16 MB (32 MB by some) limit for C .

[tnt23]

Indeed, it all depends on memory cards used. I've tested 3 different cards with AHPT94.PRG, both with ICD 6.5.5 and PP 1.03 drivers. There was almost no difference between the two in terms of performance, so I wrote down results for PP driver only.

 

512MB microSD from Nokia

• 633 K/s Transfer, 0.8 ms Access time using 'Direct HW' mode
• 635 K/s Transfer, 12.8 ms Access time using 'Logical drive' mode

4GB microSDHC by Smartbuy

• 189 K/s Transfer, 43 ms Access time both in 'Direct HW' and 'Logical drive' mode

1GB SD by SanDisk

• 844 K/s Transfer, 1 ms Access time using 'Direct HW' mode
• 838 K/s Transfer, 12.7 ms Access time using 'Logical drive' mode

Of these three cards, SanDisk is the fastest, but also rather unstable. Every now and then it is not recognized on first boot, and bombs me once in a while when running programs from disk.

[ParanoidLittleMan]

This high differences in card speeds are not normal. As said in first reply here, there is some HW problem here.

Should try at least with other DMA chip (IMP is problematic more than others), recapping PSU .

[tnt23]

I'll give those card a try with PC to see if there is any difference. Taking a look at PSU is a good idea, as its fan has become quite noisy. Don't have DMA chip replacements so I guess I'll leave it as it is for the time being.

 

As an option I can also try Ultrasatan with my other Atari 1040.