#A2500 questions
61 messages in this thread
I recently provided services for a company in exchange for a new Amiga.
They wanted to surprise me and sent me the computer they had purchased
directly from Comodore. The setup is as follows:
Amiga 2500
68020 accelerator card
3 megs RAM – 1 meg chip and 2 megs 32 bit RAM on the accelerator
40 Meg hard drive
flicker fixer
Magnavox VGA monitor
Not being too knowledgeable about the extra hardware, having upgraded
from an A500, I read up on it and now have some questions.
1) How does the 68020 compare to the 68030? The 68020 also has the 68881
floating point math chip and the 68551 MMU.
2) The 68020 will allow another 2 megs of 32 bit RAM, for a total of 4. If
I ever wanted to go beyond that, would that mean I would have to buy a 4
Meg memory board and add to that? Where would this board go and what would
be the major difference between that RAM and the RAM connected to the
accelerator?
3) I looked inside the computer and believe there is a A2090A Hard disk
controller connected to a Rodime 40 Meg hard drive. The hard drive is
connected to the 2nd 3 1/2" drive bay. I thought the A2090A was replaced by
the A2091. Since the computer is brand new from Commodore, shouldn't they
have sent the A2091? Also, I wanted a second internal floppy that the
company is now getting me. If I get the A2091, is the hard drive attached
to the card. If I don't get the A2091 can I mount the hard drive in a 5
1/4" chassis and put it in the 5 1/4" drive bay, thereby freeing up the
second 3 1/2" bay for my second floppy drive? I also thought I would be
getting a Quantum hard disk drive. Has anyone heard of Rodime?
4) The company is sending me a Magnavox VGA monitor for use with the
flicker fixer. I don't have the model number, but are the cables from these
monitors usually compatible with the flicker fixer port. If not, where can
I purchase the correct cable or does one have to be made?
A turnkey system like this is great, but the documentation for it is
rather sparse. Any help answering all these questions would be appreciated.
Thank you. Dom Fontana
Dom;
I believe that the 030 is a bit faster than the 020 with many instructions.
The cache is larger so loops that will fit in the cache will run much
faster. The 882 is also quicker than the 881. The 551 doesn't matter
since AmigaDOS is not using the MMU anyway. For most uses, I doubt that
you would notice much different between what you have and an 030 clocked at
the same speed.
Yes, if you wanted to go beyond the memory on the 020 board you would have
to buy and additional memory board. I suspect that you would have to buy
an 8 meg board since I have not heard of a 4 meg version. Also, your
numbers do not seem right….. I would expect to see the 020 board support
2 or 4 meg for a system total of 3 or 5 (without additional memory boards).
The additional board would definately be much slower than the memory on the
32 bit bus.
I am surprised that you got a 2090A (of course I am surprised that you got
an 020 accellerator too). The HD is NOT attached to the card on the 2091
though there is room. You can mount the Rodime in the 5 1/4 bay using an
adapter. I used a Rodime drive for several years. Shipped it across the
country and it stopped working. Suspected rough handling but could not
prove anything. Rodime has been in the drive business for many years and
makes a good drive.
No, monitor cables and pin outs are not standard. The Flicker Fixer port
connection does match one of the IBM Video Port "standards" but you need to
be careful. My Flicker Fixer manual states that the cable supplied with
the monitor should NOT be used for all of the monitor listed except the NEC
Multisync II. Redmond Cable can supply the correct cables (don't have
their address but ask since many others do have it).
73, bill
Bill,
Thanks for the answers. I may have been unclear, but I have 3 Megs of RAM,
consisting of 1 Meg of chip RAM and 2 Megs of 32-bit RAM on the
accelerator.
Where do I get the adapter to mount the 3 1/2" hard drive into the 5 1/4"
bay?
The company said they're going to get me a Packard-Bell monitor now,
instead of the Magnavox, because Micro-Way said it has the correct cable.
Do you know anything about this monitor? I'm trying to get all the
individual documentation for the hardware that was included in the setup.
Commodore only sent the standard manuals and made no mention of the
flicker-Fixer at all.
Thanks for your help.
Dom Fontana
Dom –
You might want to check with Dave Minnich in the CBMService forum (go
cbmser). He's part of CBM Customer Support and should be able to answer
your questions. I don't recall what Commodore included in some of their
package deals, so am not sure if third party hardware, such as the MicroWay
Flicker Fixer was included. Your system might have been put together by an
independent systems integrator. In any event, Dave should be able to give
you as much assistance as anyone at Commodore can.
Jeff Schweiger
Dom;
Try a computer dealer on the mounting adapter. I am pretty sure that the
Rodime will only use a "normal" 3.5 to 5.25 adapter. That is an adapter
that would adapt a regular floppy would work. A few manufactures' adapters
rely on non-standard mounting holes present on their own drive but most do
not. If you get one that uses the normal 3.5 mounting locations then all
should be ok.
From a software standpoint, you don't need anything on the flicker fixer.
It is virtually transparent as far as the amy is concerned. Once it is
hooked up it will work except that there is a phasing adjustment that may
need to be made (small hole in the mounting bracket). The phasing may need
to be adjusted if you see a small amount of jitter in the image. If you
don't have a flicker fixer manual and MicroWay or CBM won't send you one,
let me know as I should have a spare around here somewhere. Some add on
video hardware will occassionally have problems with the flicker fixer. If
you encounter such problems, give MicroWay a call as they are VERY good
about helping with problems.
Welcome to the world of Amiga. It may take you awhile to get used to
multitasking but once you do, nothing else will please you! Also, on this
forum…."the only stupid question is the one that you don't ask!" You
will find that most folks here will go to a lot of trouble to answer any
questions that you might have. Many of us sat in front of that original
A1000 with almost nothing in the way of documentation and prayed for
someone to talk to that could share experiences.
73, bill
Many 3.5" drives come with a drive-bay adapter (as my Seagate 1096N did).
They can also be obtained from most dealers that sell hard drives.
Chris,
Thanks for the information.
Dom Fontana
Dom,
I cannot answer ALL those questions, but I can answer some. I have a
2500/030 and a Flickerfixer. Before that, I had a 2000HD with the 2090A
and a 40M Rodime drive. It autobooted, worked fine, and I had no
complaints about it.
I'm surprised that a new machine would have either the /020 card OR the
2090A, though. I got the 2091 with my 2500 machine in January, and it came
with a Quantum 40M drive.
The VGA monitor is fine, but less versatile than a multisync. I have a
multisync myself, and my cable came from Redmond Cable in Redmond, WA. They
seem to know already just what to do for cables for the Amiga. I just had
to tell them the brand and model of my monitor and they did the cable.
If you put another 2M of memory on the accelerator card, it will be 32-bit
memory, and will work faster than the 16-bit memory you would put on a
memory card, or on the 2091 controller card if you have one of those.
Betty
Betty,
Thanks for the reply. It seems everyone is surprised that I got the 2090A
instead of the 2091. I thought they discontinued the 2090A and I don't know
why they would give it to me in a brand new system. When you got your
2500/30, did you have a choice of hard disk controller cards or did the
2091 just automatically come with it?
How much memory can you install on the 2091? If it takes another 4 Megs
then together with the accelerator I would never need another memory board;
just the chips, right?
Thank you,
Dom Fontana
This sounds like one of the systems that Commodore put together for dealers
as a desktop publishing system. If they didn't include a flickerfixer
manual, call Microway tech support at (508) 746-7341 and ask for one. You
will need a flickerFixer to VGA cable which can be provided by Redmond
Cable, (206) 882-2009 (west coast) or (615) 478-5760 (east coast). Peter.
Peter,
Thanks for the information. You mentioned that it sounds like a system
Commodore put together for dealers as a DTP system. How long ago was this?
Also, would you have any idea why I would get this system? In other words,
did Commodore send an old system?
Thanks,
Dom Fontana
I want to know what you did to deserve all that hardware! 🙂
Dom –
Sounds like you got a nice setup. While I cannot judge whether or not
it is a fair exchange for your services, I believe strongly that you did
not get a "new" Amiga. CBM stopped making and selling the 2500/20 in 1989
or very early this year. They have been selling machines with the Quantum
HD and A2091 controller since before January 1990… I bought an A2000HD
last March after several months of waiting.
– Nelson …
Nelson,
Thank you very much for the information. I suspected Commodore had pulled
a fast one. I agree that the system that they sent is excellent, and I'm
grateful to have it, but they sent an outmoded system. It would be like
buying software from a company and they sent you an older version. If the
2500/20 was replaced by the 2500/30 in 1989, then Commodore had no business
selling a discontinued model.
Thanks for your help.
Dom Fontana
Dominick, I was not aware that Commodore charged the same for the 2500/20
as they do for the 2500/30. And is there is a real difference?
Chris,
I believe there is about a $800 difference in price between the 2500/20
and 2500/30.
Dom Fontana
However, older technology is not necessarily less desirable. The A2090a
controller supports both IBM-type and SCSI-type hard drives, and the former
have been cheaper than the latter.
THol() { cout << "Sir, I exist." ;}
Thomas,
I know that, but isn't a SCSI drive better than an IBM-type? The 2090A
uses the ST-506 Rodime drive. A number of people have told me that a SCSI
drive is much better than an ST-506 drive. Also, I heard the 2090A crashed
often especially when used with overscan. I was also told the 2091 was much
faster than the 2090A. Finally, the 2091 has room for 2 Megs of Ram, the
hard drive can be mounted on the card itself, and it lists for the same
price as the 2090A.
Do you have any knowledge of the differences I mentioned above? If they
are true, why would anyone want a 2090A instead of a 2091, since they both
cost the same?
Thanks,
Dom Fontana
Dom;
The reasons are getting weaker but the ST-506 interface type drives were
very much cheaper than the SCSIs at one time (they still are a little
cheaper but not worth the difference).
Yes, there were overscan problems with the 2090/2090A controllers. The
last of the drivers cleared up most of the problems as far as I know (I am
still using a 2090 in an Amiga 2000 w/GVP 030 and do not have any problems
with overscan). Of course the 030 may have some effect on that too.
Bill,
I guess I could live with the 2090A, but if you were buying your hard
drive controller now, would you buy the 2090A or 2091? I guess the company
thought I wouldn't mind since it is my first hard drive. But, I do mind.
Just because someone gets their first car, doesn't mean it has to be a
Yugo.
Dom Fontana
Dom:
Another thought might be GVP's upgrade offers, they have 2 right now, 1 is
a tradin/up of disk controllers (you send your controller, and some money,
and get their newest controller), and many consider their stuff better than
CBM's, and the other idea is to upgrade your 2620 card with their 3001
board, as it has an ST-506 style controller built-in, that works somewhat
faster than CBM's, and has less problems in general.
-Mike Schiller
In sunny Fort Lauderdale
Mike,
I might consider those options if CBM doesn't allow me to exchange the
controller. Thanks,
Dom Fontana
Mike,
unless something has changed, I thought the controller was an IDE which
is why your pretty much stuck with buying their drives.
Brian J. Bartlett
Brian:
Perhaps I'm now showing my ignorance of PC style HD's. Is there a
difference between an "ST-506" style drive, and an "AT" style drive? I
thought they were the same.
-Mike Schiller
In sunny Fort Lauderdale
Mike,
The ST-506 drives were used in the IBM-AT with the standard controller. A
new style of drives has emerged, called IDE (for Integrated Drive
Electronics), which, for some reason unknown to me, is also called an 'AT'
drive. The latter type is the one used with the GVP-3001.
Hope this helps. 8)
David
Mike,
They are NOT the same. "AT" drives are NOT ST-506.
Victor A. Wagner, Jr.
I see the others answered the question, so I'll just make an addendum.
ST-506 and IDE/AT, no comparison! <grin>
Dom, the 2090A is not a BAD card, but the 2091 is faster. I don't think
you will find it slow, though.
Do you have the system? If not, wait till you get it and decide for
yourself.
— Ethan
I don't want to use the system until I decide. I won't be able to exchange
anything if the system is used. That was the whole point of soliciting
opinions of users who have already tried one or both controllers, so I
could decide without using the system myself. Also, when I do use the
system, I'll have no basis of comparison with the 2091. I'm sure I'll be
delighted with the 2090A as compared to floppies, but I might have been
more delighted with the 2091. This is what I'm trying to determine before I
use the system.
Thanks,
Dom Fontana
My God! You have a system sitting in front of you and you've resisted
the temptation to plug it in! Sheesh!
Ethan,
Re not plugging in the system, I have a lot of self control. Actually, I'm
still using my A500, so it's not that bad. I have someone who is buying my
500 and I'm waiting for my CBM 1950 monitor to arrive. I'm also waiting for
a determination as to whether I can exchange the controller and drive. I
don't want to set up the system and then tear it down again. I'm trying to
orchestrate everything so that I can simultaneously sell the 500, set up
the 2500, and leave it set up.
Dom Fontana
Unless there was a slowdown between the 2090 and 2090A, I consistently get
better diskperf and diskspeed results on the 2090 as compared to the 2091.
I'm not sure if I'm doing something wrong in setting up the 2091, but I'm
using the standard 2091 setup disk. So I'm not convinced that the 2091 is
faster.
I have been told of wierd results with the diskperf program and don't
totally trust it. The 2091 should be a faster card, but of course the drive
matters as well.
— Ethan
Well I tried 2 different diskperf type programs "Diskperf 2" by Khalid and
MKsofts "Diskspeed 3.1". Both programs indicated that the 2091 was slower
than the 2090, using the same drive a Quantum 105s. I've also been getting
a larger number of read/write errors since I switched to the 2091. I've got
an external 20meg SCSI drive hooked up to the 2091 along with the Quantum,
and I read in some earlier threads that the 2091 is having problems with 2
or more SCSI devices hooked up. Sounds like Commodore needs to fix a bunch
of problems in the 2091.
John:
I have 2 drives on my 2091 and have had no problems at all with errors.
This arrangment has been in use for almost a year.
>> Gary <<
I'm happy that you're not having any problems with your 2091 Gary. But a
few of us are having problems and mine didn't show up until I switched from
the 2090 to the 2091, so I think I have a valid reason to suspect the
controller. Maybe we can blame it on Gremlins 8^)
The main reason I'd like a 2090A instead of a 2091 is that ST-506 drives
are cheaper than SCSI drives, and the 2090A handles both. I personally
prefer cheap, slow drives and a huge RAM cache (using Blitzdisk2) to more
expensive, fast drives and a small RAM cache. Infinite resources would
clearly mean fast drives and lots of RAM, but within the limits, I'd rather
have $200 more RAM than $200 faster drive.
THol() { cout << "Sir, I exist." ;}
Thomas,
I'm not certain I understand you. Why does the 2090A have a huge Ram cache
and the 2091 a small Ram cache? How do you figure the 2090A has $200 more
Ram and the 2091 has a $200 faster drive? Also, isn't a SCSI drive
preferable to a ST-506 drive?
Dom Fontana
I mean, if I have a certain amount of money to spend, I can get better
system performance (for _my_ applications) by economizing on the hard drive
(in terms of speed) and spending the savings on additional RAM. Thus, the
2090A, which allows me to use cheaper ST-506 drives _as_well_as_ SCSI
drives, for that reason allows me to implement my slow-drive big-RAM
strategy.
Thomas,
In other words, buy cheaper drives, save money, and get more ram. What are
your applications anyway? Also, are you happy with the performance of the
2090A?
Dom Fontana
My applications are programming, communications, drawing, and music. I'm
delighted with the performance of the 2090A.
THol() { cout << "Sir, I exist." ;}
Thomas,
I shouldn't have a problem with Midi software or with large sound samples
with the 2090A, according to you experience?
I forgot. Do you have the Rodime drive also? How many megs?
Dom Fontana
I don't know whether I have a Rodime or not.; I bought the A2500 about six
weeks after its release. I'd be extremely skeptical of any scheme to
handle large sound samples other than reading them all into FAST RAM to
start and then swapping them into CHIP RAM, so a few ms on the hard drive
won't make any difference.
Thomas,
Good advice re sound samples. I'll be keeping my 2090A and Rodime and I'm
sure it will be fine.
Dom Fontana
Thol:
The price difference is mainly a thing of the past. Looking at the
DC Drives ad in Computer Shopper, here are a few comparisons:
ST-506 SCSI 20 meg ST-125 $229
ST-125N $279 30 meg ST-138 $279 ST-138N $319 80
meg ST-4096 $559 ST-296N $439
ST-506 drives no longer have a $200 advantage.
Clint <VRLI>
Dom,
Among other things – the 2090A can handle two ST drives AND a full set of
SCSI drives. The 2091 does not handle the ST drives at all – and the ST
drives are not nearly so expensive. This is important to some people.
Actually, I have the 2090A-Rodime drive on a 2000HD that my husband uses,
and the 2091-Quantum40 on the 2500 that I use. I've had really good
service from both of them. I had really thought that the 2090A had been
discontinued, though.
It occurs to me that the company might have purchased one of the DTP
special offer units in order to get you the flicker fixer at a price they
could afford. I don't recall seeing the FF advertised with any other
system from Commodore, and last spring, they were advertising a special for
DTP that included just the system you are describing. Perhaps the FF was
the deciding factor.
Betty
Betty,
You're right on the money! The outside of the box says, "Amiga 2500-DTP".
Since you've used both controllers, could you please verify what I've
heard. (I do apologize for asking so many questions).
Does the 2090A crash frequently and have problems with overscan? Since the
2090A doesn't boot from the FFS is it demonstrably slower than the 2091?
In normal usage how much slower is the 2090A than the 2091?
What are the advantages of a SCSI drive over an ST-506 drive?
Thanks again for your help.
Dom Fontana
Dom,
I had a very small – about 1M – boot sector on the Rodime drive, and then
the rest of the boot process goes onto the FFS part of the drive. The
drive is actually 43M instead of 40, so you don't really miss a lot there.
I did not notice it being slow. Also, I didn't notice problems with
overscan, but then – I rarely use overscan. I thought there was a program
that cured that problem, though, and that it had been incorporated into the
later models. Wish I knew more about this, but I don't.
As for crashes – I had more with the 2500/2091 than with the 2000HD/2090A
for quite a long while. A bit of work, and a different Agnus chip changed
that, and now I'd say both machines behave in about the same way for me.
SCSI drives are usually faster than ST drives, and the SCSI is a rather
loose standard of drives that should work on any machine. Problem is, the
standard is not always implemented the same way.
Surely some others will chime in and give you more information here.
Betty
Betty,
As usual, your help has been invaluable. I should know what's happening
very soon and then I can just enjoy the system.
Thanks,
Dom Fontana
Dom,
No one ever reported an overscan problem with an ST-506 drive on the
2090, only SCSI drives.
Victor A. Wagner, Jr.
Vic,
I don't know why and will not question it, but, I've got a 2090 with 2
ST-506 HDs and a SCSI HD connected to it. I also run overscanned to the
max. I've never noticed any perceptable (ible, able? Who knows?)
slowdown.
-sja
Steve,
I've noticed a slowdown of the SCSI drives only when running
overscanned and interlaced modes. No slowdown on the ST-506 drives. Any
other video mode there's no slowdown at all.
Don
Don,
As I said, I've noticed no slowdown — my default configuration is
710×476. I would assume that qualifies as "overscanned and interlaced".
Vic,
So you recommend keeping the 2090A?
Dom Fontana
Dom,
If you're only gonna have ST-506 drives on it, I don't see why you would
want to spend the extra money.
Victor A. Wagner, Jr.
If I may make some suggestions based on my experiences with Hard Drive
controllers…
Hardframe – Hands down, the fastest ICD Advantage – Economical, fast, and
no DMA problems A2091 – Excellent controller, especially if you don't have
expanded ram
already.
Tom Gandey, Gold Disk
Tom,
I appreciate your reply, but I'm not quite certain if you were following
the whole thread. I agreed to accept a new Amiga from a client for services
rendered in lieu of cash. They got me an A2500 directly from CBM, since
they are an Amiga developer and can get a big discount. The system was the
discontinued A2500 DTP package with 2620, 3 Megs, 40 Meg hard drive,
Flicker Fixer, and 1950 monitor. Great system, but it comes with the A2090A
controller instead of the A2091.
The purpose of the thread was to ascertain if the A2091 was that much
better than the A2090A, to warrant my trying to exchange the controllers
through CBM, which would have been a major undertaking. The general
consensus was to keep the system as is, which I am doing.
So although I appreciate your recommendations, I am not in a position to
consider any non-CBM controllers.
Thanks anyway.
Dom Fontana
Then may I say…. 2091, 2091, 2091, TINAR, 2091, 2091.
I have an A3000 (32-bit 2091) and I am very pleased performance wise.
Tom Gandey, Gold Disk
The big difference between the A2090(a) and the A2091 is their SCSI
handlling. I went through this problem when I upgraded my A2500/020's HD
to an 81MB Seagate ST-1096N SCSI. The older A2500's (the 68020 versions)
all came with the A2090(a) controller. When doing SCSI handling in
interlaced video modes, there was an incredible amount of DMA overhead
introduced. It caused the video chip and the HD controller to compete for
DMA time, and would basically lock up the HD. It could take several
minutes to load in an interlaced image due to the conflict. The only way
around it was to switch over to a non-interlaced screen, and the contention
would disappear. I eventually gave up on the A2090(a), after talking to
Commodore shops, and finding that they would NOT do a trade-up on it.
I first tried a Kronos controller, which got rid of the DMA problem, but
introduced another problem: I would be downloading, the comm software
would write out to the HD, and due to it's handling, would introduce
transmission errors into the dload. Finally, I got rid of the Kronos (it
was fast, but the modem problems I couldn't handle) and bought a Xetec
Mini-Fastcard. This is a dedicated SCSI controller, and has some advanced
DMA handling routines which eliminated all contention problems! And to
boot, it was about $200 cheaper than either the Kronos or Commodore's
controller. Any questions? Feel free to ask…
Ted
Ted,
Too bad you didn't ask about that Kronos "problem" here. There would
have been a very simple solution – one that was mentioned in the Kronos
documentation. Just by changing "Disable_IRQ" to "NoDisable_IRQ" in the
"DEVSetup" file for the drives. There would then be no contention with the
data coming over the serial port – and therefore no problems with
telecommunications programs.
I tried the Xetec Fastcard before the Kronos, and there *was* NO
COMPARISION. I've been trying the TrumpCard Pro, and with the same drive it
*STILL* isn't as fast.
Oh, well. If only the company that is *supposed* to be supporting the
Kronos would ADVERTISE them!
Lloyd