On Apr 20, 14:06, Max Eskin wrote:
> Could someone tell me what the configuration of individual gates
> is (one of them, at least) for binary addition (or provide an EASY
> TO FIND reference)?
This sounds like a homework question... Well, I suppose all classic computers
have adders in them. You want to look up "half-adder" and "full-adder". A
half-adder adds two binary digits, to produce a sum output and a carry output.
A full adder is, not surprisingly, two half adders, wired so that it also has
a carry-in. You can make a half-adder from an XOR gate and an AND gate, though
that's not exactly how they're usually implemented. How to make a multi-bit
adder with look-ahead carry is left as an exercise for the reader :-)
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
<Boy I'd pay $100 for a working PDP11/23 with RL02's (at least one workin
<and bootable).
<
<Bill
get out a scrounge around. 11/23s are common as house flies. you should
be able to find one for free that is usable. The common problem is you
can find just the cpu box (cpu, ram, IO, maybe disk controller) but no
drives.
The thing is with RX02s for $100 is possible, with RL02s no way. RL02
drives used go for more than that alone. I'm looking for a RL02 drive
myself as I only have one, they are scarce and expensive.
SCSI boards and eithernet cards same thing, expensive. CPU boards, maybe
$20-40.
The problem is most cards compatable with an 11/23 are also compatable
with most of the qbus VAX systems other than memory(usable but far too
slow and limiting in other ways.).
Allison
Could someone tell me what the configuration of individual gates
is (one of them, at least) for binary addition (or provide an EASY
TO FIND reference)?
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No connection to this person whatsoever. Thought this might be of
interest to some.
>
>I have an Adam computer that I want to sell. It is in perfect working
>condition. All the original equipment including the box is intact.
>Serious offers can find me at
>
>mtruman(a)usa.net
>
>Mike
>
>
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(Home of the COSMAC Elf Simulator!)
>
>
> <Boy I'd pay $100 for a working PDP11/23 with RL02's (at least one workin
> <and bootable).
> <
> <Bill
>
> get out a scrounge around. 11/23s are common as house flies. you should
> be able to find one for free that is usable. The common problem is you
> can find just the cpu box (cpu, ram, IO, maybe disk controller) but no
> drives.
Up there maybe... down here in NJ they're rare. Sun boxes are
around (Sparc), I even saw DECstations, RS6000's but no good looking
Vaxes or 11's. I think the area scrapped most of 'em 4 years ago.
At this weekend's Trenton Fair (which used to have
8's, 11's and Vaxes -- nothing below a Microvax chassis...).
And this was a big DEC area until the late 80's. I worked it for years.
>
> The thing is with RX02s for $100 is possible, with RL02s no way. RL02
> drives used go for more than that alone. I'm looking for a RL02 drive
> myself as I only have one, they are scarce and expensive.
>
> SCSI boards and eithernet cards same thing, expensive. CPU boards, maybe
> $20-40.
>
> The problem is most cards compatable with an 11/23 are also compatable
> with most of the qbus VAX systems other than memory(usable but far too
> slow and limiting in other ways.).
>
> Allison
>
I turned down an 11/34 with RL02 for $25.00 four years ago because the
OS's weren't easy to come by and the boxes were larger than I could
transport in my compact car (at the time I didn't have my good old
DECwagon available).
Ah @!#$%^&. I could sure use it now.
This seemed to be the year of the $10 MacII at the show. I picked
up some Mac stuff for fun... but I'd love to populate my VT103 out.
Bill
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I made a small neural net, non-learning, in Visual Basic (hey! it's
easy!), available at alt.ne.mediaone.net/zeus334/neural.zip.
Also, there was just a short segment on TLC on truck collecting.
Very interesting. Maybe I'll collect old trucks AND old computers!
This was talking about a new englander who collected big trucks.
His favorite was a chain drive 1932 german truck...
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This is the case for the april early birds from what I saw last year.
As the season progresses (MIT is every month) the mix changes.
< He also had an 11/23 he wanted to sell for $100 and _wouldn't_
< budge. He told me they were 'classic' computers and could
If it were an 11/20 or 11/05 it's collectable.
Numb is correct. 11/23s are common as house flies and though they are very
classic and somewhat desireable for pdp-11 hackers he's out of his mind.
Last year there was someone there doing same and I ended up taking it home
for free as he couldn't bring it back. Now consider this he was offering
an 11/23 complete with RX02 and 2meg memory, plenty of serial IO and TWO
complete copies of RT-11v5, two sets of diagnostics disks and two RT11
doc sets.
If he parted it out and sold it to one of the used DEC resellers he might
get 100$ for the peices total.
<PS - I would have paid up to ~$20 for the 11/23, but $100?????
thats about right IF it's at least a complete CPU/mem/io/disk! With some
software and known operating $50 may not be out of line. more than that
it better be pristine, FULL COMPLETE DOCS and actually running.
Allison
If the modem is the thing w/ 5 pin DIN socket, I have one.
What is Data General's number?
> does it have the built in modem? That's the only option I don't have
for
>mine. Also, if you could gently remove the disk drive buttons and send
them
>my way, I'd be appriciative. Mine broke off.
>
> -spc (You might want to call Data General and see if they have
replacement
> LCD screens, or at least where you might get some)
>
>
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