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Amiga computer related discussion => Amiga Software Issues and Discussion => Topic started by: leytond on February 27, 2009, 05:12:28 PM

Title: MaxTransfer , how and where.
Post by: leytond on February 27, 2009, 05:12:28 PM
could this be the root of my problems installing classicwb,
all i get is error code 50 while trying to unpack to hdd on a real amiga, not that emulator rubish. ive heard "MaxTransfer" could be the problem, where is it , what is it, and can i alter it,
Title: Re: MaxTransfer , how and where.
Post by: Matt_H on February 27, 2009, 05:22:17 PM
Open up HDToolBox. On the change file system page, you should see a string gadget containing the max transfer value. Change it to 0x0001FE00. You might need to reformat afterwards.
Title: Re: MaxTransfer , how and where.
Post by: leytond on February 27, 2009, 05:39:16 PM
string gadget containing the max transfer value. Change it to 0x0001FE00
first, im a total newb to this as they call me on eab,
second what is a string gadget and what dose it look like, .
third reformat, that means that i have to put os back on,
Title: Re: MaxTransfer , how and where.
Post by: Ilwrath on February 27, 2009, 05:51:50 PM
Quote

string gadget containing the max transfer value. Change it to 0x0001FE00


It's just a spot where you can type in a value.  It'll probably have 0xFFFFFFFF in it.  That is a bad value.  The A1200 HD controller has a nasty buffer bug that shows up on certain hard drives.  The Max Transfer value needs to be something much smaller.  There is some debate over what an optimal value is, but that 0x0001FE00 should work.  

Quote
third reformat, that means that i have to put os back on,


You won't HAVE to.  But, the problem is, while the max transfer was incorrectly set, every file larger than about 256kB or so written to that hard drive has a chance of being corrupt.  Who knows how many problems are lurking undiscovered in a system like that.
Title: Re: MaxTransfer , how and where.
Post by: Zac67 on February 27, 2009, 05:57:09 PM
0x0001FE00? Where does that value come from?

I've always had the impression that 64K is a limit on some systems, so something like 0x0000FF00 would be logical (wouldn't make much of a performance difference anyway). Could someone enlighten me?

PS: didn't know about the 1200 IDE bug, my systems have always been 'pure SCSI'. ;-)
Title: Re: MaxTransfer , how and where.
Post by: leytond on February 27, 2009, 05:57:26 PM
i dont get it, if its going to corrupt the files what is the point of doing it,
wont it fix it, .
Title: Re: MaxTransfer , how and where.
Post by: Ilwrath on February 27, 2009, 06:04:15 PM
Quote
i dont get it, if its going to corrupt the files what is the point of doing it,
wont it fix it, .


The files already copied may already be corrupt.  You can't do anything about those.  That's why it's recommended to format and reinstall.

Setting the new value will allow NEW files written to the drive to be written properly.
Title: Re: MaxTransfer , how and where.
Post by: leytond on February 27, 2009, 06:06:53 PM
right ill go and give it a go, but knowing my luck ill be back with a ton of questions.
nothing works with this amiga,
Title: Re: MaxTransfer , how and where.
Post by: Ilwrath on February 27, 2009, 06:09:11 PM
Quote
0x0001FE00? Where does that value come from?

I've always had the impression that 64K is a limit on some systems, so something like 0x0000FF00 would be logical (wouldn't make much of a performance difference anyway). Could someone enlighten me?


I'm not positive.  Personally, I ran 0x0001FFFF back in the day.  That was what the local C= dealer recommended.  I've heard all three values cited.  I've never heard of anyone having problems at 0x0001FE00 or less, though.  (And, personally, I never had any problems at 0x0001FFFF on a drive that had loads of problems at the default value.)
Title: Re: MaxTransfer , how and where.
Post by: davideo on February 27, 2009, 06:27:42 PM
The thing to remember with changing the max transfer value is to make sure that you press ENTER/RETURN otherwise the value won't be saved.

Dave G  8-)
Title: Re: MaxTransfer , how and where.
Post by: alexh on February 27, 2009, 07:51:21 PM
Quote

Ilwrath wrote:
0xFFFFFFFF is a bad value.  The A1200 HD controller has a nasty buffer bug that shows up on certain hard drives.

AFAIK the bug is not with the Amiga but in the drives.

Quote

Zac67 wrote:
0x0001FE00? Where does that value come from?

Unknown. Trial and error? It should be just less than 128Kbytes or 64Kbytes (the two most common maximum sizes used by OS's today) Windows uses 64Kbytes. Some CF cards are very picky and people have said the only transfer size that worked for them was 0x0000FE00

Title: Re: MaxTransfer , how and where.
Post by: leytond on February 27, 2009, 09:18:50 PM
well yep i changed it , and yes pressing enter sure dose help, as i found out,.
well like i said ive done it, i dont know what its supposed to do , but my hard drive is still working,
what is it supposed to do??
Title: Re: MaxTransfer , how and where.
Post by: Matt_H on February 27, 2009, 09:41:30 PM
It reduces the amount of data copied in a single "cycle" of a disk transfer operation. It's set fairly high by default (good for SCSI drives), but IDE drives tend to barf on it, resulting in corrupt data. The new values you've seen in this thread should help.

Also note that you need to make the change for every individual partition.

If you're new to the Amiga, be aware of the infamous >4GB problem. What size is your drive?
Title: Re: MaxTransfer , how and where.
Post by: leytond on February 27, 2009, 11:30:12 PM
my drive partisions aer.
dh0: 2gig
dh1: 10 gig
dh2: 10 gig
dh3: 10 gig
 and the os3.5 with 2 boing thingy updates.
Title: Re: MaxTransfer , how and where.
Post by: Trev on February 27, 2009, 11:40:16 PM
And based on past observations, I'm under the impression this is a signed value, so 0x7fffffff would be the max, anyway. Anyone know for sure? Dependent on the device driver's interpretation of the data?
Title: Re: MaxTransfer , how and where.
Post by: Zac67 on February 28, 2009, 03:22:28 PM
Quote
And based on past observations, I'm under the impression this is a signed value, so 0x7fffffff would be the max, anyway.


LOL - just show me an Amiga with a RAM amount just remotely close to that value and I'll gladly explain everything to you...  :crazy:  ;-)
Title: Re: MaxTransfer , how and where.
Post by: Matt_H on February 28, 2009, 07:55:25 PM
@ leytond

That setup is probably fine. You can verify it with Check4GB (http://aminet.net/package/disk/misc/check4gb).

Are you still having problems unpacking the archive? Maybe your version of LhA is too old.
Title: Re: MaxTransfer , how and where.
Post by: Trev on February 28, 2009, 11:54:57 PM
@Zac67

:-P My point, of course, was that 0x80000000 = -1 and any device that can transfer negative blocks of data certainly deserves our attention. ;-)

WinUAE supports up to 1.5GB, so it's almost there. I forget why Toni stopped there, but I think he's explained over on EAB. So, an OS3 device driver could, in theory, use a MaxTransfer value approaching 2^31-1 if Toni bumped up the Z3 memory emulation. :-)

And there's OS4 and MorphOS to consider. Did device driver tooltypes carry over to those with the same semantics?
Title: Re: MaxTransfer , how and where.
Post by: Zac67 on March 01, 2009, 09:35:44 AM
Quote

:-P My point, of course, was that 0x80000000 = -1 [...]

Obviously you mean 0xFFFFFFFF = -1, 0x80000000 = -2^31

AFAIK there are numerous issues with invalid signed long usage in AmigaOS, so anything beyond 2 GB is out of the question. Actually I was trying to refer to a real Amiga that even with several DKB3128s (or extremely rare) upgraded Fastlanes is far below that mark. :-)
Title: Re: MaxTransfer , how and where.
Post by: Trev on March 01, 2009, 04:41:08 PM
Uh, d'oh! Yes. :-) The point of my point ;-) was the sign bit, so I could fib and say I meant -1 * n or something like that. Pardon me while I bludgeon myself with a two's complement primer.
Title: Re: MaxTransfer , how and where.
Post by: rockape on March 01, 2009, 07:40:05 PM
Hi,

see http://wonkity.com/~wblock/a1200/a1200.html

"Q. I have have no idea what the MaxTransfer value should be for my drive. What value should I use?

 A. For unknown drives, the maximum "safe" value is 0x0001FE00. Other (older) drives may require 0x0000FFFF or even 0x0000FE00. The sure test is to copy files larger than the MaxTransfer value to and from the drive, checking for corruption afterwards. Pictures work well for this, as corruption is easy to detect."

Regards, Michael

aka rockape