Once upon a midnight dreary, R. Stricklin (kjaeros) had spoken clearly:
>On Wed, 2 Dec 1998, Tony Duell wrote:
>
>> If the RTC chip is much taller than the other chips on the mainboard (say
>> about 3/8" high) then it probably contains an internal battery. Dallas
>> and Mostek/SGS-Thomson made chips like that.
>
>It is. I forget offhand who made it, though. Would it be powering the
>NVRAM, though? On a SPARCstation you actually have to replace the NVRAM
>chip itself. I guess it couldn't hurt to try to replace it.
If the markings are for a Dallas 12887(a) then the NVRAM is integrated with
the clock chip & battery. To my knowledge, the closest person to being
world-famous for changing a Dallas battery would be Dr. Marty Goodman, of
CoCo fame. IIRC, he's a member of a mailing list gatewayed to the newsgroup
bit.listserv.coco, so if you send a message there, he should eventually get
it (along with everyone else on the gatewayed list, so pose it as a
CoCo-ish question... tho CoCoists (IMHO) aren't quite as rabid as some
other platform gurus...)
>> You're supposed to replace the chip when the battery fails (after about
>> 10 years). I have heard of people carefully slicing the top off the
>> package and replacing the lithium cell inside, but I've not had to do
>> this myself - yet.
If it is a Dallas 12887 (without the "A" suffix), I can tell you this:
beware of the Dallas 12887. The 12887 has one shortcoming: the NVRAM
*cannot* be reset via external means, which means if whatever machine has
fouled the NVRAM so badly it can't boot, it'll *never* boot again without
replacing the chip itself. Some PC's used this chip, and said machines are
a thorn-in-the-side when their NVRAM settings go haywire.
IIRC, the Dallas 12887A is pin compatible, and *does* have an NVRAM reset
pin... I also know that you can get all the pin info & other stuff from
Dallas's website, which is slightly confusing at: http://www.dalsemi.com/
Watch out, tho: All their datasheets are in PDF format, so you'll want to
grab Adobe's Acrobat reader to view the sheets with.
The page with all of their PDF's for their chips is:
http://www.dalsemi.com/DocControl/PDFs/pdfindex.html
Hope this helps,
Roger "Merch" Merchberger
Ethan Dicks said:
>I am cranking along with the capture of the Elf99 design ....
I just found this thread. This is a great idea and should have been
tried sooner. I'll buy one.
>Did I miss anything? Any other suggestions?
The only thing I see missing is the expansion bus connector.
(Did I miss that part?)
There are hundreds of things that would be nice to have, but it's
important that the design be finished and the boards made. Leave the
bells and whistles to the end users. If you create an Elf that can
address about 2K, has a small prototype area, and has a good
expansion bus, then all things are possible. (Including S-100 interface)
You should copy one of the two Super Elf buses.
> A protoyping area of .1" spaced plated-through holes, nominally
> a few inches long by one or two inches wide.
A prototype area should be for wirewrapping. I don't see any need
for plated-through holes, and pads are not REALLY necessary either.
>I will not be including space
>for an 1861 because I have been entirely unable to locate a source.
The 1861 should be easy to add on later. In the prototype area or hot melted
to the top of another chip. Just make sure it's easy to cut the trace for the
original clock circuit and wire in the new one.
>Ooh. What a concept. I know there is a CHIP-8 emulator page out there.
>Perhaps there is a source version of the interpreter floating around.
I think there is a source code listing in Paul Moews book on
Elf interpreters.
=========================================
Doug Coward
Press Start Inc.
Sunnyvale,CA
=========================================
The key to the elf design was minimalism and low cost.
Substituting a latch and LEDs for a binary display instead of the til311
is cheaper and more buildable.
using modern cmos and rams help.
The basic elf was far to minimal and frequently expanded to get desired
functions. The basic design did not easily permit that as it didn't
decode memory or IO addresses.
The RCA VIP or the 18S020 Evaluation board allowed far more flexibility
with relatively little more logic. Thei cost was they had some rom.
The 18S020 board was 4k ram (1822s), two 1852 as parallel io ports, UT4
monitor rom (512bytes) and another 32bytes for monitor storage. It used
Q and EF3 for TTY/RS232 and the bus was available with numerous decodes
at the edge connector. It also had LEDs for data, address and processor
status lines (binary).
This is a reproducable design. UT4 fits in 512byts of a 2716, the rest of
the ram can be done with byte wide parts. The 1852s can be kept and the
rest were common 40xx series. With 4k of ram and UT4 (or similar)
programs like PILOT, TinyBasic, or some of the other neat software with a
terminal.
A much simplifed machine using 1802, 2 1852, 2 4028, 2 4042, 1 62256,
1 2716 and 1 6116, some glue logic for reset, run, runp and the same
serial scheme as 18S020 would give 32k of contigious ram, 2k-32byts in the
>8000h area and the remaining 1.5k in the 2716 could hold any number of
things along with the .5k ut4 monitor. This would be a very useful
system that could accomodate expansion for IO (more ram??????).
Allison
Did anyone go to the Birman's Diversified Auction, I think on Tuesday, to see
what VAX stuff was there? I am interested in how the sale went and what kind
of prices things brought. Please reply to me at Whoagiii(a)aol.com.
Thanks,
Paxton
>I constantly drool over stuff that's in the Charles Babbage Institute's
>archives, but I don't get to Minneapolis very often (OK, I *never* get to
>Minneapolis).
>
>Are there any Minneapolitans (?) out there willing to copy a few goodies
>from their archives? I'd pay for copying, shipping, gas, and probably a
>coupla bucks more.
I can't volunteer, since I'm usually working during the hours the Institute
office is open.
Anyone thinking of dropping in on the Institute should be aware that their
building will be extensively renovated during 1999-2000. Accordingly, they
will be in temporary quarters for quite a while, and I suspect much of the
collection will be inaccessible during that time.
For those unfamiliar with the Babbage Institute, they have a fair amount of
material available at <http://www.cbi.umn.edu/>.
>(besides, what else are you going to do when it's snowing
>out?).
That's never a problem. I'm always figuring I'll get projects done "during
the winter," and I rarely get done with more than a handful of them. :-{
----
John Dykstra jdykstra(a)nortelnetworks.com
Principal Software Architect voice: +1 651 415-1604
Nortel Networks fax: +1 612 932-8549
I think INIT's corrupt. Specifically, SAVRES.
I'm trying to shove the RA81 on a tape. I say SAVRES, from DU0: to MS0:,
and it says INITIALIZING FIRST SAVE SET or something along those lines,
shoves the tape around for about 45 minutes, then says STARTING SAVE FROM
DU0: TO MS0: AT XX:XX AM (or something similar) and hangs there (not doing anything)
for a few minutes, after which it traps through 10. (Illegal Instruction, I
think...)
Does anyone have a RSTS 8.0-07 tape I can suck just INIT off of? Is there
any way to do this under timesharing? I don't have BACKUP...
Seems someone's removed that too.
-------
Hey guys.....
I have a bunch of TRS-80 Model II 8" software discs with original programs
on them..... Anyone have a clue as to how to Archive them?????
"Programming today is a race between software engineers striving to build
bigger and better idiot-proof programs, and the Universe trying to produce
bigger and better idiots. So far, the Universe is winning." -- Rich Cook
> From: Philip.Belben(a)pgen.com
> Subject: Re: Audio Cassette formats; Copy protection?
>
> >::There are plenty of ways of preventing a BASIC program from being
> listed.
> >::Dunno how you prevent it being saved (and say 'BAD PROGRAM'), but I
> could
> >::probably figure it out given time... Anyone else?
The popular (quick) way was to put an RTS in the second cassette buffer with a
SYS in the code pointing to it. (on the PET) and save the program from that to
the end using the MLM. Then if someone SAVEs it regular and tries it it just crashes.
The most ingenious PET protection was to put a bit of code in the FIRST
cassette buffer, so you had to save it from the second cassette port using the
MLM to make a runnable copy. Second would be to plug a bit of code into the
chargot (I think) routine in low memory which will trick the computer in
running the program once loaded (this could easily be bypassed on the PET, but
on the 64, it was pretty fool-proof.
On the 64 if you can get to the vectors before the user can try SAVing, you
change the jump address for SAVE (locations 818,819) to your own location.
> > On the 64, you could type
> >
> > 10 remL
> >
> > (rem, then a shifted-L)
> >
> > and LIST will stop up with a ?SYNTAX ERROR when it hits that line.
> Rather
> > easy to defeat but annoying as heck. :-)
>
> Same on Basic 2 PETS. On BASIC 1 you used shift-K.
The character varys on the computer. I think Transactor or Compute did a
table of em once.
> Possibility that I thought of, but didn't try. Make the initial line a v.
> high line number (>63999). Have the program start rem L, then disable the
> stop key, then poke that line number to something smaller. Bit harder to
> defeat but won't deter the determined cracker.
>
> Mean trick I did use. In the middle of a subroutine I entered the line
>
> REM@TURN
>
> I then found the @ sign and poked the location with 20 (ctrl-T, the PET
> backspace)
>
> This now lists as RETURN but does nothing...
So was this to twart those modifying the code, or tracing it?... Oh... add a
REM shift-l after it, once the 'fix' it it still doesn't work.
Only problem with the delete character is if you list to a printer they will
all show up.
>
> Philip.
That same PET program had an ingenious listing protection too, the first two
lines were only listable and they were effectively masked by rems with a bunch
of delete characters. What the programmer did was break the line links after
the second line so the computer thought it was a two line program. But when
run the two lines restored the link via POKEs, once it was running past that
point, it restored the line break.
If you are curious to see this marvel in action it is on-line; check out my
Flash Attack page and download either of the PET versions, this was written by
Tim Stryker years before he founded Galacticomm.
Hi!
Anyone have a hard drive controller for a Tandy 1400HD laptop that they'd
want to sell? The one in mind recently died, and when I turn it on, all I
get is a blue screen. I disconnect the HD, it starts to boot (BIOS number
comes up), then stops, and starts emitting a fish-like smell. I pull the
controller entirely, and it works fine (with no fish smell).
Any suggestions (other than getting one from RadioShack)?
ThAnX,
--
-Jason Willgruber
(roblwill(a)usaor.net)
ICQ#: 1730318
<http://members.tripod.com/general_1>
>> Possibly. But I distinctly recall that when we recorded tapes for sale
>> using the tape deck from my Sanyo stereo (not on a PET BTW - this was a
BBC
>> micro) we found that Dolby noise reduction had to be disabled for it to
>> work...
>
> Did you try recroding with Dolby and then replaying on a machine with
> Dolby noise reduction (turned on), or replaying on the normal cheap
> cassette recorder that you use with computers? If the former, then I am
> not suprised it didn't work - the frequency response would have been
> rather odd. The latter should have worked, though.
We didn't try recording with Dolby and playing back without. I'd be very
surprised if that worked (did you mean it that way round). I can't
remember if we recorded with and played back with - I imagine that would
work - but we definitely couldn't get it to work recording without and
playing back with, although this actually works quite well for music.
> I would be suprised if you couldn't make a CD that could be loaded. I
> can't try it because I have no way of writing to a CD.
I never meant to imply that you couldn't make a CD that could be loaded.
What I meant was you probably have to be more sophisticated than old
cassette -> digitised audio -> audio CD. I'd recommend old cassette ->
signal restoration -> digital signal (0s and 1s sampled at some highish
speed) -> possibly prefilter to pre-emptively undo the CD player's output
filter -> digitised audio -> audio CD.
For PET (and family) tapes a C2N would probably make a good cassette
machine for playing it initially, since it does some of the signal
restoration itself.
Philip.
