Mounting real CF eats up a lot of RAM

[Toni Wilen]

You could try few more buffer values (lowest allowed is 10) and take a note of available memory to confirm if it is buffers or something else that eats too much memory. 1 buffer should be about 1k of memory.

Always power off and then on and boot without-startup sequence to 100% confirm it isn't some setpatch stuff that eats memory.

Filesystem handler itself (code and data) requires about 60k so technically with buffers and other structures pfs3 should not require more than 100k or so of memory. If only single partition.

[Amiga1992]

So I still have 200KB of overhead.
I will try other buffer values and see what's up.

[Skylight]

Originally Posted by Toni Wilen

1 buffer should be about 1k of memory.

This depends on block size.
1024 bytes is maybe the default value in HDToolBox (e.g. 45.6), but i would always choose 512 bytes to reduce the slack space.
There is not much difference in performance.

EDIT: Or is PFS3 fixed to a block or buffer size of 1024?

EDIT2: block size can't be fixed since i see a big difference between drives with different block sizes but same content

[Toni Wilen]

One PFS3 buffer is always 1024 bytes, it is independent of block size.

[jbenam]

Sorry to bump, but I can confirm that this still happens.

I installed PFS3 (latest version) on my A1200 unexpanded with the standard 30 buffers setting (I have two partitions) and I found myself with 300kB less of Chip RAM

Reducing the buffers for both drives to 10 "fixed" the problem

I don't use a CF but a 2.5" 700MB IBM drive, if that matters.

[Amiga1992]

I just gave this a try again, the best performance was obtained indeed with "10" as buffer value. With 2 partitions, the system now "eats" 350KB.

Still, makes me wish I had some Fast RAM to leave more Chip RAM clear, I am using these machines for my PT-1210 sets and the reduced RAM doesn't let me load a few of the bigger modules.

[Retrofan]

Originally Posted by Akira

I just gave this a try again, the best performance was obtained indeed with "10" as buffer value. With 2 partitions, the system now "eats" 350KB.

Still, makes me wish I had some Fast RAM to leave more Chip RAM clear, I am using these machines for my PT-1210 sets and the reduced RAM doesn't let me load a few of the bigger modules.

Could you please upload to the Zone any of those bigger modules to try with your wonderful PT-1210?

[alewis]

Just a thought. The standard File systems used a block size of 512bytes, the standard buffer size was 512bytes. So adding 30 buffers per drive used 15Kb per drive/partition for each entry. Iirc it defaulted to 30 buffers per HD and 5 per floppy unless overridden in the RDB or startup-sequence.

SFS and PFS used a larger block size, partially to improve read performance and to cope with larger hard disks. As such, the size of a single buffer would need to increase to match the corresponding block size. Consequently, if a block was now 1024bytes, each buffer would be 1024bytes, and 30buffers would use 30kb. Did PFS not also include a disk cache? This would also use a buffer size that matches the block size, but would also be increased by the number of cache lines. Ie, a cache of 30 buffers with a line size of 10 would use 300Kb, as it is equivalent to 10 lots of 30 1024byte buffers.

I also have a vague memory that if you had buffers specified in RDB, having an addbuffers command in startup allocated those as additional buffers.

Probably wrong, as it's been nigh on 20years since I used a real Amiga in anger.

[Amiga1992]

I'm still trying to figure this out. I now have two exact A600 2MB systems, and I am, in both, left with almost 1.6MB of RAm. EAch partition seems to be eating up 100KB of RAM, regardless of their size (in one case Work partition is 200MB, in the other it's 900MB).

I really can't afford to change to FFS and risk data loss or stupid validation processes. I use these machines live and need them to be reliable.

[daxb]

I haven`t read the thread so it might be obsolete. PFS3 docs say that it uses at least 70 kbyte Buffer or max 500 kbyte for a partition. If Buffers aren`t resposible for the loss of memory you might analyse chipram. You might see what kind of code is there.

[Jope]

If you don't want to push a RAM board onto the CPU, why not get some PCMCIA SRAM cards to alleviate your pain?

[Amiga1992]

Originally Posted by Jope

If you don't want to push a RAM board onto the CPU, why not get some PCMCIA SRAM cards to alleviate your pain?

Well those aren't cheap usually and also, I use the PCMCIA slot for reading data off an SD card (this is why I don't need that second partition you told me to not mount ).

I would love to install a kipper 4MB upgrade but I had problems with a machine with an ACA620 and it snapping off the socket in transport. Now it's bolted and seems stable but the more shit I add inside, the more in the computer that could go wrong. Trying to keep the system really simple and transport/bump-friendly.

I don't really understand buffers though. The same amount of RAM is taken with 10 buffers, regardless of the size of the partition. Is this right?

[Jope]

Yep, what you ask is what you get, apart from if you run PFS3 and ask for 30, you get 150.

[Amiga1992]

Yeah that's why I reduced it to ten, 30 was taking the piss.

[Amiga1992]

Well this is as far as I managed to go:



1.8MB bytes free, 284KB in use

I suppose there's no way to disable DF0: without a modified Kickstart?

[Jope]

Try to disable df0: in the early startup menu. Then you'll also want to run add44k..

[Amiga1992]

Yeah my problem is I don't use a mouse with this setup at all, so early startup is out of the question
Once the system is shut off, add44k will probably not matter, right?

[Jope]

If you allocate the RAM neatly before switching the system off, then it will matter.

[Amiga1992]

I will give it a try! See what happens. Thanks Jope

[Jope]

Np, hope it helps.