From: bmccnnll@unix1.tcd.ie (Barry McConnell)
Newsgroups: comp.sys.amiga.hardware
Subject: DMAfix (Was: Is anyone out there using a Mega Midget Racer w/ GVP HD)
Date: 3 Oct 92 00:53:17 GMT
Organization: Trinity College, Dublin

In <67041@cup.portal.com> Neon@cup.portal.com (Anthony Joseph Bruder) writes:

>In an article 9/30/92 Barry McConnell writes:

>My mask is already set to 0xfffffffe but I still had the slowdown without
>using DMAfix.  Could be my old prep program was not doing the job correctly
>and preping the drive with the new program I have now seems to do the
>trick.

Interesting... I haven't heard of the prep program "not doing the job
correctly" on any other system. Did you do it for all partitions? Did you
try using HDToolbox as well? (Add the ToolType SCSI_DEVICE_NAME=
gvpscsi.device)

>However, using DMAfix still adds some more speed.

As I always ask DMAfix users: how much more speed do you get relative to
a) The GVP's solution (high mask), and b) The FileSystem's solution (mask
something like 0xfffffe)? I collect DiskSpeed outputs. :-)

>The trouble here is that the 32bit ram on the MMR daughter board is not
>autoconfigured and is *outside* the normal 16 MB address space.

Same on both accelerator cards I've had the pleasure of owning...

>The mask,
>as I understand it, tells the drive where it can't DMA not where it can.

The mask (if I may quote Ralph Babel - hi Ralph!) is a fix for bad device
drivers. *Everything* should work with a mask of 0xfffffffe. If it doesn't,
it's bugged. It should work out for itself what to do when it encounters
non-DMA memory. The GVP Series II does a DMA to lower memory, and CPU-copies
up (same as DMAfix). The later A2091's kick into PIO mode (ouch!). I don't
know about other controllers. If you use a lower mask, it means it's up to
the FileSystem to sort out the problem, which (even under KS2.04) it does
very, very, very, very, very, very, badly. You may be forced to do this if
your controller barfs on non-DMA memory (like my old A590), and that's why
I wrote DMAfix!

>I would be interested in getting the registered version of DMAfix but am
>always reluctant to do so outside the US.

I appreciate that. I have however had registrations from the US before, and
there were no problems (aside from a temporary postal strike at the time...).
The reg'd version has one change: it can use 16-bit Fast RAM (as opposed to
Chip RAM), which is considerably faster. You *must* have KS2.04 in ROM for
this to work - check that a later version of SysInfo reports your 16-bit Fast
RAM to be MEMF_24BITDMA if you want to know if the reg'd version will benefit
you.

Of course, even if you're running 1.3, you should register anyway! :^)  
(Support Shareware!)

>Barry McConnell asks for
>10 Irish/UK pounds or its equivalent.  Don't know what to send in $$ with
>conversion rates and increased mailing costs for him do to overseas mailing.

The exchange rate is all over the place at the moment (the Irish pound is worth
more than the Sterling pound for the first time in several decades...), but as
a (very) rough guideline: there are 2 dollars to the pound. 10 pounds would be
$20, or maybe a little less.

>Also I'm uneasy about sending cash through the mail.  Most authors won't
>accept a check since they lose so much in bank charges for overseas checks
>and currency conversion.

I've had both cash and a (US) cheque: both are fine. I am really lucky in that -
as a student - my bank doesn't charge me for cashing cheques in a foreign
currency. You can even send a bank draft if you like!

>BTW he mentions in the docs, something about e-mailing the registered
>version.  This would save him the overseas shipping charges and speed
>things up.  I know my e-mail address as neon@cup.portal.com, but for
>international mail would I  add the suffix .us as in neon@cup.portal.com.us?

Easy! E-mail me privately, and I'll know what reply-address to use! 

>Anyhow, thanks for the reply to my post and any further information would
>be gratefully recieved.

You're welcome...

Barry.
bmccnnll@unix1.tcd.ie
Newsgroups: comp.sys.amiga.hardware