Eric Smith <eric(a)brouhaha.com>
> Cameron Kaiser <ckaiser(a)oa.ptloma.edu> wrote about undefined 6502 opcodes:
>> [lot deleted]
Exact hit Eric.
> This is nothing new to microprocessors; many mainframes and minicomputers
> had undefined opcodes which customers experimented with.
Yes, but as a rule, mainframes and most minis catch undefined
opcodes in a special exeption. Even the Intel x86 (starting
>from with the 80186) throw an Int 06 on invalid opcodes.
> As with the
> microprocessors, there was never any guarantee that the undefined opcodes
> on any two otherwise equivalent machines would peform identically. With
> microprocessors, though, there tend to be fewer design changes made after
> introduction than there were for mainframes. AFAIK, all NMOS 6502 CPUs
> have the same behavior for all undocumented instructions. Some of the
> NMOS deriviatives have different behavior though.
Jep, the web article used by Cameron as reference is
based on the Commodore 8502 used in the C64. Just
lucky that Commo used the original MOS design for
the 8502 :). Other 6502 compatible Processors, that
didn't use the original design have different operations
at the undefind opcodes. Eventualy this led to some
problems Apple II programms encountered on individual
clones or Apples with upgraded CPUs. Especialy when
one switched for any of the CMOS types (65C02, 65SC02,
65G02, 65S02), becuse they used some of the free Opcodes
for new/enhanced operations (like bitmaipulation etc.).
Undefined opcodes ar implementation dependend like
internal function of an operating system are version
dependand. Just remember how ridicoulus the CPU detection
algorythms on the x86 are since there was no standard
cpu type command. Some of the enhanced chips can only
be detected usind complex tryal and error strategies.
I remember that a general purpose detector could take
some seconds to determinate the CPU thru exeptions,
timeouts, busfaults and arithmetic checking.
And now try to distinguish the different 6502s. I have
never seen any programm to perform this.
Funy thing: History repeats with DirectX - Microsoft
didn't include any version checking in DirectX 3.0
so, for example, if you want to use the enhanced sound
functions later on, you have to perform time consuming
operations to finaly find the needed function resulting
in an error (or worse, depending on the function just
performing diferent).
Gruss
H.
--
Ich denke, also bin ich, also gut
HRK
Whoa!
Yep, that's the one! Boy, did you ever get lucky! Those current tracers
are $300-$400 a shot! And HP *still* makes these.
Such a deal.
On Thu, 08 Oct 1998 18:40:44 -0700 Bruce Lane <kyrrin(a)jps.net> writes:
>At 00:44 09-10-98 -0000, you wrote:
>
>>I've lusted after the HP Current Tracer for years, but they are very
>>expensive and the price keeps going up!
>
> Is this the probe that looks a lot like the later models of HP
>Logic
>Probe, except with an insulated tip and a little pot that's used to
>set the
>sensitivity?
>
> If so, I got lucky and found one at a local swap meet. I think
>the guy
>wanted all of $25 for it and the HP Logic Pulser. I got both,
>naturally.
>
> I would conclude that they do show up at techie swaps, but not
>that often.
>
>
>-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>Bruce Lane, Owner and head honcho, Blue Feather Technologies
>(Hamateur: WD6EOS) (E-mail: kyrrin(a)jps.net) (Web:
>http://table.jps.net/~kyrrin)
>SysOp: The Dragon's Cave (Fido 1:343/272, 253-639-9905)
>"Our science can only describe an object, event, or living thing in
>our own
>human terms. It cannot, in any way, define any of them..."
>
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Someone suggested H11 and I'd bet that one is more encumbered as it was
a version of RT and I think Heath was licensed from DEC.
< Obviously, I don't own a license for RT-11. And assume that the commerci
< license from Mentec is probably much more than a hobbyist would pay to
< tinker with old machines. Has anyone approached Mentec about the
Unknown, Megan any idea of cost?
< they would be more apt to create one. From what I can tell, an old PDP
< with no software license is virtually useless, except for
< hacking/curiosity value. After a half hour of playing around with the
Maybe someone could create an OS for the PD, patterned after CPM or ???.
< would be without the VMS-hobbyist license. I mean, who _really_ wants t
< run BSD on all of your old hardware? It kind of defeats the whole
< purpose of collecting the old machines if you have the same stupid Unix
< prompt on your VAX, Sparc 1, Mac IIfx, 486PC, etc...
That is especially true if your not into unix though, that is an option
for those that are.
Allison
< V5, V6 and V6 are available from the same site as the Supnik
< emulators, and I don't believe the licenses accompanying them
< are as strict... and yes, the license for them is only $100.
The 100$ license is for the sources. Binaries are pretty much free if
it runs on what you have. It turns out that can be more of a restriction
than any license.
The question is however is there something else? I know fuzzball is
around but I don't know if that is a option for most -11 users.
For me it's no fun running an emulator when real iron is at hand. Though
I'm able to run most OSs I'm always looking at "Yet other choices".
Allison
< address of 4200H or something for TRS-80 Model 1's without a memory
< mapping mod, and also for some Heathkit machine. I always assumed the
< latter was the H8.
All of the H8 and H89 systems were rom at 0000, mods were available for
both.
Allison
one of my 3 apple //GS wouldnt power up which after subbing parts out, turned
out to be a power supply issue. i took the cover off the ps to look around
finding nothing obviously wrong. i looked at the fuse and wasnt sure if it had
burned out or not. call me crazy or whatever, but i used a paper clip to
bypass the fuse and plugged the ac in and powered on for just a sec. i got a
bit of smoke so i powered off and checkes. not finding the source, i did it
again while watching. this time, something really smoked! it seems to be a
small transformer of some sort, about 3/4 in square and 1 inch high and it's
right near where the a/c comes into the power supply. there's a larger one
right int he middle of the circuit board. it's still hot several minutes
later! thankfully the computer itself is ok although it did reset my main
computer on the same electrical outlet. provided i didnt destroy the whole
bloody thing, what could be causing the problem?
david
I was thinking I had seen it in 80 Microcomputing. If I get time this
weekend, I'll see if I can find it. My memory is hazy on the issue, but I
believe I either sent them money for a product, or was _about_ to send them
money when it turned out to be a scam. I remember things like mock-ups of
products that they used in their ads; they'd taken some standard project
boxes and literally just sat parts of switches, LED lenses, etc, on top of
them for the photographs. I think I may have talked to someone at the
"company" about their products. If I can ask, what prompted this after so long?
>
>But can anyone point me to a particular issue of Byte or other
>magazine that has a World Power Systems ad?
>
>- John
>
>
Bill Richman
incolor.inetnebr.com/bill_r
(Home of the COSMAC Elf
microcomputer simulator!)
If anyone wants to know about the Cat, I have a large collection of info and
Cats (and a Swyft or two) and a lot of memories.
John 'Sandy' Bumgarner
job(a)garlic.com (sherry(a)neteze.com is my wife's email address)
>::Jep, the web article used by Cameron as reference is
>::based on the Commodore 8502 used in the C64. Just
>::lucky that Commo used the original MOS design for
>::the 8502 :). Other 6502 compatible Processors, that
> Luck had nothing to do with it -- Commodore owned MOS. MOS was turned into
> Commodore Semiconductor Group after Jack Tramiel bought them out.
Stupid meone, no idea of history.
Gruss
H.
--
Ich denke, also bin ich, also gut
HRK
This particular manifestation of a hard drive problem is not classic,
but since it could just as easily happen on a classic computer, might
as well ask it here. If you think it's inappropriate, please say so.
The machine in question is a Mac Quadra 610, which has been running
as a fileserver for a 15-machine network for many years. It has an
8GB hard drive, probably one of the first to get into catalogs. It
was working OK, but tended to freeze when four people started to
transfer 10MB files. So, we replaced it. And now, the hard drive
stopped working and we can't get the documents stored on it back.
Here is the hard drive problem: it spins up ok (takes about 15sec.
and sounds like a hair dryer when it does), and then tries to seek.
The heads sound OK for about 1 sec. and then make a clicking noise and
stop. It then tries again. Does this mean some servo data has been
overwritten or something? We don't want to spend $1000 on recovery, and
I thought this might be a good time to try some alternative methods.
Would it help if I opened the drive and manually moved the heads?
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