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From: mykes@3comvax.UUCP (Mike Schwartz)
Newsgroups: net.micro.amiga
Subject: Re: Fraud And Deceit In The Memory Board Market
Message-ID: <574@3comvax.UUCP>
Date: Wed, 9-Jul-86 13:10:51 EDT
Article-I.D.: 3comvax.574
Posted: Wed Jul  9 13:10:51 1986
Date-Received: Fri, 11-Jul-86 07:17:00 EDT
References: <1353@well.UUCP> <1811@shark.UUCP> <567@3comvax.UUCP> <1400@well.UUCP>
Reply-To: mykes@3comvax.UUCP (Mike Schwartz)
Organization: 3Com Corp; Mountain View, CA
Lines: 47
Keywords: A *purported* Buyer's Guide

In article <1400@well.UUCP> perry@well.UUCP (Perry S. Kivolowitz) writes:
>In article <567@3comvax.UUCP>, mykes@3comvax.UUCP (Mike Schwartz) writes:
>> know what (maybe someone who knows can fill us in).  Also, the AddBuffers
>> command in 1.2 uses chip memory exclusively, so it is not possible to add
>> as many as 750 buffers (I wish I had 2MB and could add 1788 buffers to
>
>This is because DMA is controlled done on the internal (512K limited) bus.
>
Obviously the dma for the disk drive works in only the lower 512K of memory,
but that does not preclude moving the buffers to fast memory with the CPU.
When you have ram and floppy disks (i.e. no hard disk), backing up the ram
disk becomes the biggest problem facing you.  Right now, I use MAKE to 
back up sources and objects as it makes the program, but it would be ideal
if I could simply add 750 buffers to each disk and use these buffers as
a cache.  My development habits would not have to change with/without the
extra RAM, everything that needed to be in RAM would end up there 
incrementally as I do things.  Anything I expect to be written to disk ends
up on disk automatically.  750 buffers is not unreasonable, when you consider
that that is < 440K.  440K taken away from my chip memory is unreasonable.
So, I guess the bottom line is that the AddBuffers command is a great first
step toward making the machine faster with floppies, but it still doesn't
do exactly what I would like it to do (granted, it is only my wish, I have
not seen anyone else request it yet).

So for now, I use 30 buffers for both drives and have to hack at my makefile
to get the desired effect.  This is ok, but it could be friendlier, in my
humble opinion.

>What does CardCo suggest as to how many cards can be added after the CardCo
>RAM card? Related question: how much current does the board draw? Are there
>any by-pass capacitors on the board? By-Pass cap supress noise but drive the
>cost of the board (more holes to drill) up (plus the cost of the caps). Many
>would argue, however, that having them (one or two per ram chip) is worth 
>while.
>
>Perry S. Kivolowitz

Apparently, the Cardco boards draw 390 MilliAmps, so two boards can be
plugged in at one time.  They do pass through the bus, and the only 
problems I have had with it are the logistics of using it efficiently
and reliably.  I haven't taken it apart, but I do have high confidence
in CardCo, since I have seen LOTS of their products and they ALL have been
correct.  I would recommend the board to anyone who is looking for RAM.
The cost is fair, and it is a well done product.  It is supposedly the
first board that does follow the Amiga add-on specs.  It doesn't appear
to have the ability to be plugged into a card cage, but since it passes
the bus, a card cage can still be used with it.