BB memory cards
10 messages in this thread
Paul,
The Rambank is a memory card for expanded memory and filling
conentional memory, i.e., it can be used for filling 512K out to 640K with
the rest going for expanded memory. It is made by Diamond Flower Electric
Instrument Co.
The Rambank is sold as MEMO-2000X by Alex Electronics, Inc., Mail Order
Dept. 11342 IH-35 North, San Antonio, Texas 78233. Their order number is
(800)531-5369. The price is $79 without memory. (You can GO DA to Delco
Electronics for some good chip prices or call 1-800-445-5342 for a price
quote.)
It is described as 256K to 2 Meg LIM/EMS compatible. Uses 4164 or 41256
DRAM chips (probably 150 ns, I bought 120 ns and 100 ns chips). Can
backfill conventional memory from 256K to 640K. Includes EMS drivers, RAM
disk and print spooler.
BTW, this is not the only choice, of course, for adding memory. I use
it for a ramdisk. Since my AST SixPakPlus fills up my conventional memory,
the 2 meg is currently allocated as expanded memory. Of course, I could
remove the AST card for another card and use some of the 2 meg to backfill
conventional memory and use what's left for expanded.
Sincerely,
(Mr.) Gayle Lee Fairless
'Perfessor Fearless'
Hmmmm, You're getting me closer and fasterer up to speed 🙂
When I use the left over memory as "expanded memory", does this allotment
get used a lot by typical IBM software? I see a need at times for "video"
memory.
Many thanks for the help,
Paul
–pt–not seattle– 😉
Paul,
You might want to ask someone else about typical IBM program memory
allocation with regard to specific titles. I know general information
especially since I've programmed in Z80 assembly language and am familiar
with CP/M, the ancestor of both MSDOS and DRDOS.
I was mainly interested in the expanded memory for a ramdisk so I
could use it as a work area like I use the one at work on the Zenith AT and
use the ramdisk on the Amiga.
Sincerely,
(Mr.) Gayle Lee Fairless
'Perfessor Fearless'
Gayle: A RAMdisk is useful on MS-DOS machines, but generally (not always)
an even better use of memory above 640K (extended or expanded, depending on
your processor, not to mention "high" memory between 640K and 1 meg) is a
disk cacheing program. Has the advantage of needing less memory to do the
same work as a RAM disk. Think about it. To run an application faster via
RAM disk, you've got to load it into the RAM disk, which takes x memory.
Then you call into operating memory, which takes another x of memory, for
2x. A disk cache reserves a portion of operating memory (extended or
expanded, if you have it) and swaps code in and out of the cache, which is
held in operating memory. 1x!
Still better are programs that automatically find free EMS RAM and plug
straight into it. You can have all three: RAM disk, disk cacheing software
and applications, plus an OS like DR-DOS 6.0, loaded all or partially into
EMS. >> Ron Legro / Milwaukee
via WHAP!
Ron,
If I remember correctly, DRDOS 6.0 has caching if the user wants
it. Since I have 2 meg on the Rambank, there should indeed be enough room
for all three! 🙂
Getting the jlink virtual drives to work would give me another
ramdisk if I use RAM: on the Amiga side.
Sincerely,
(Mr.) Gayle Lee Fairless
'Perfessor Fearless'
Ron,
Disk caches don't run programs from within the cache…but rather
they simply buffer the most recently read/written sectors from the disk in
RAM.
Thus, depending on the size of the cache…to load a program you
end up with 2 copies in RAM, the running program, and the cache'ed program
read from disk.
Cache programs show their greatest useability during things like
text editing, database operations or any other operation that is constantly
reading and/or writting data. As an example, suppose a text editor reads
in 100 sectors (and thus those 100 sectors are also in the
cache…presuming it's large enough). You edit the file, but only change
data in one small area. On writing the file out, the cache only writes out
that one small area…possibly only 1 sector. Thus avoiding writting out
the 99 unchanged sectors and thus speeding up things greatly. Now if you
suddenly decide to re-edit that file, it's already in the cache…thus
takes essentially 0 time to read in.
The same idea applies to database access and so forth.
CPU caches operate the same way…except with program instructions
and data thus speed up execution.
But neither of them gives you 1x size of the program only in RAM,
they end up with the loaded program, plus some amount in the cache thus you
end up with somewhere between 100% and 200% of the program in some form of
RAM.
Don
Yes, I understand that. I was speaking too loosely. What I tried to say
(and your message explained better) is that a disk cache can be more
efficient where a program running in RAM goes to data or overlays
frequently. With a RAM disk, you'd have 2X the size of the program plus
associated files in RAM — the running copy and the copy on the RAM disk.
With a cache (as you said, depending on size) you can cut down that ratio
appreciably in many instances without affecting the improved performance.
>> Ron Legro / Milwaukee
via WHAP!
Paul,
I'll sell you a 2 meg card with backfill….
Fred E.
Thankyou for the offer, I have to count cards and slots first. I think I
may need a multi-function card to get all I need in.
Paul
–pt–not seattle– 😉
Paul,
The best a multi-function card can do is give you 640K, but no extended
memory….
Fred E.