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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Cosmos Amiga on June 12, 2011, 04:17:36 PM

Title: How are working U901 & U902 A4000D IDE 3.5 ?
Post by: Cosmos Amiga on June 12, 2011, 04:17:36 PM

The scsi v40.12 (Kickstart 3.1) and the v43.45 (Boing Bag 2) use big loops for copying files. It's IDE, not SCSI, all is done by the CPU !

On the A4000D, these loops give a faster transfer rate when using .w (16 bit) than .l (32 bit)

On the A600/A1200, .l is faster...


Maybe I found why big loops .w are faster than .l in the read/write function on the A4000D scsi driver : PM me for explanations if you know how are working U901 & U902.
These two Gals need a simple fix (I hope) for working faster using .l !


I use this funny trick to get all ax+0 / ax+1 / ax+2 / ax+3 using big loops .l all the time in my scsi beta :

- ax+0 => loop .l
- ax+1 => .b + .w => loop .l => .b
- ax+2 => .w => loop .l => .w
- ax+3 => .b => loop .l => .w + .b

... and I wanna use it into the A4000D scsi driver, of course !!

Title: Re: How are working U901 & U902 A4000D IDE 3.5 ?
Post by: freqmax on June 12, 2011, 04:40:37 PM

Grammar and problem description is not working :P

Title: Re: How are working U901 & U902 A4000D IDE 3.5 ?
Post by: yaqube on June 12, 2011, 05:35:16 PM

http://eab.abime.net/showpost.php?p=603519&postcount=39

Title: Re: How is working U901 & U902 A4000D IDE 3.5 ?
Post by: Cosmos Amiga on June 12, 2011, 06:19:53 PM

I wanna use .l now, no more .w ! I'm not talking about PIO !!