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#: 22830 S13/GEOS in General
29-Apr-90 22:38:34
Sb: #GEORAM VS. REU1764
Fm: Heyward Boyette 74620,2012
To: [F] Ed Flinn/Sysop and a 76703,4032 (X)
ED, and ANYONE with opinions on REU 1764 vs. GEORAM. I just purchased a 1764
REU for my son and am going to purchase one for myself, or a GEORAM. I would
appreciate opinions on which might better suit my general needs. It seems that
the extra 256k with the GEORAM would be nice but is it worth the sacrifice of
being bound exclusively to GEOS. While I have just recently started usiing
GEOS, I still have and use many non-GEOS software programs(all productivity, no
games). Cadpak, Chartpak, Microsoft Multiterm, and many others. The price is
about the same so my dilemma really is: will the 1764 work with most
productivity software, is the 256k adequate for most
C= 64 software to get the maximum benefit, and is the 1764 adequate for GEOS?
I plan to order today or tomorrow so any thoughts to help me
decide would b appreciated. Also, has anyone come up with a retrofit for the
1764 to increase its memory? <<<<<<<HEYWARD>>>>>>
#: 22831 S13/GEOS in General
30-Apr-90 15:35:04
Sb: #22830-GEORAM VS. REU1764
Fm: Ed Flinn/Sysop 76703,4032
To: Heyward Boyette 74620,2012 (X)
Heyward,
It's probably safe to assume that commercial software not specifically
written for RAMDOS won't work with it. There will be exceptions, but I don't
own any of the software packages you mention, so don't know if they can be made
to work properly with it. If anyone else here does know, I hope they'll chime
in.
The 1764, in GEOS mode, will be able to either act as a RAM 1541 disk, or
else to "shadow" a 1541. Shadowing is similar to what the IBM types call
"cacheing," where each sector, as it is read, is stored in the REU. The next
time that sector must be read, it is read from the REU, not the disk. Writes
to disk take place immediately. Shadowing has most of the benefits of a RAM
disk, with the added benefit of automatic writing to a real disk.
geoRAM, with 512k can be used as a RAM 1571, or to shadow a 1541, and have a
RAM 1541, or to shadow two 1541s.
In LIB 13, we have an ARC file, EXPAND.BIN, which contains a geoWrite 2.1
document that details stuffing a 1764 to 512k. Obviously, doing so voids your
warranty, and is to be done at your own risk.
#: 22836 S13/GEOS in General
30-Apr-90 16:49:34
Sb: #22830-#GEORAM VS. REU1764
Fm: <]Dave[> 72030,661
To: Heyward Boyette 74620,2012 (X)
Heyward; the 1764 uses DMA (Direct Memory Access), which is somewhat faster
than what you can get with geoRam. GeoRam is limited to Geos only, and only
through 256-byte "windows". Get the 1764, and upgrade it to 512K, as the other
message indicates. I've seen the instructions, and anyone who can solder can
do the upgrade. <]Dave[> 72030,661
#: 22846 S13/GEOS in General
01-May-90 15:54:31
Sb: #22836-#GEORAM VS. REU1764
Fm: Heyward Boyette 74620,2012
To: <]Dave[> 72030,661 (X)
DAVE, Thanks again for your comments. I ordered a 1764 today and will have it
Thursday. I got one for my son last week and I plan to expand
both to 512k. I was scouting around for chips today and found prices from $4.60
per chip to $11.95 per chip...what a price spread.
I assume that any 256k by 1 bit Dynamic RAM chip will do the job. If you or
anyone else reading this can shed any further light on the RAM chip specs,
please respond. Oh, I also believe that the chip must be a 100nanosecond speed
chip. Dave, what do you when you say that the GEORAM uses 256 byte "windows"? I
know that 8 bits make one byte, but not much beyond that. I'll let you know how
I make out. I also learned that RAMLINK, available from CMD, makes the 1764
compatible with most software. I won't be getting that anytime soon, but it was
another reason to go the 1764 route. Do you know of any other ways to achieve
ompatibility with non-geos software? Thanks again, <<<<<<<HEYWARD>>>>>>>>
#: 22848 S13/GEOS in General
01-May-90 22:17:27
Sb: #22846-GEORAM VS. REU1764
Fm: Joe Buckley 71570,2600
To: Heyward Boyette 74620,2012 (X)
Heyward,
If you want a good price for 41256-150, call B.G. Micro in Dallas at
(214) 271-5546.
The last price I had from them (January) quoted $1.90 per chip.
That's virtually free!
Joe
#: 22851 S13/GEOS in General
02-May-90 18:32:53
Sb: #22846-GEORAM VS. REU1764
Fm: <]Dave[> 72030,661
To: Heyward Boyette 74620,2012 (X)
Heyward: The price spread you're seeing is related to the speed of the memory
chips; if you look at the chip numbers, you should see something like 41256-12
or -15 or -8 (or 08). This is the speed of the chip in 10's of nanoseconds-
thus a -12 is a 120nS ch chip. I suppose you COULD try 150nS chips, but you'd
probably be better of using 120 or 100's. If you have a look in the DL13 forum,
you sh should be able to find a text file about the geoRam; it should help
point out a few of the major differences. As for teh 256 byte windows, 2^8=256.
Why geoRam is limited to only 256-byte windows is beyond me- something to do
with the chips they used to make it, I imagine, as well as teh lack of DMA
(Direct Memory Access- FAST!) C= has the rights to their Ram Expansion Co
Controller chip (I suspect a factory-masked controller chip), but there are
other ways to get around it- they're just more complex and expensive. As for
the RamLink stuff, I wouldn't think that you'd need it- if the software
recognises the 1764, tehn the RamLink is superfluous (sp?) (read:uneccessary).
If you go through your 64 (old one, or the 64C that came bundled with geos?),
it should say in there if it supports the 1764, by using commands like STASH
FETCH and SWAP. Also, the 1764 is SUPPOSED to come with some utilities and such
that allow use with the 64 in native mode. Hope this helps. <]Dave[> 72030,661
P.S. Sorry about the message, but I'm in CPM mode, and CServe doesn't work the
same this waymessages tend to get a little garbled because I don't get the
end-of-line bell......
#: 22852 S13/GEOS in General
02-May-90 18:37:09
Sb: #22846-GEORAM VS. REU1764
Fm: <]Dave[> 72030,661
To: Heyward Boyette 74620,2012 (X)
I almost forgot: the "window" refers to how much of the REU the computer can
see at a time- 1764's should be able to find several K of memory (perhaps as
much as 64K, I'm not sure of the specs); but the geoRam can only access the REU
in 256 byte chunks.....something of a difference, I'd say!
Of course, if you can access those 256-byte chunks fast enough, it wouldn't
matter much; but there are limitations due to teh hardware. You can APPROXIMATE
DMA without actually using DMA, but you can only get so close- if you wanted to
go any faster, you'd have to USE DMA. <]Dave[> 72030,661