BIG ol tektronix scope 555 - need it gone - make an offer

[Marc Howard]

That's a beautiful old scope setup.  I have a friend who collects this
stuff but he is very low budget and on the opposite side of the country
like me.

Marc

On Tue, Dec 11, 2018 at 6:15 AM Paul Koning via cctalk <
cctalk at classiccmp.org> wrote:

>
>
> > On Dec 11, 2018, at 7:59 AM, Toby Thain via cctalk <
> cctalk at classiccmp.org> wrote:
> >
> > On 2018-12-11 1:17 AM, devin davison via cctalk wrote:
> >> The line about being used with an early computer as a display caught my
> >> eye. How would it be used as a display, what kind of graphics capability
> >> would it have? is there an interface for the thing for the pdp 11 or a
> >> modcomp? Those are the old systems i have on hand that i might be able
> to
> >> interface to it.
> >
> > A scope is at heart an electrostatic CRT with X and Y deflection (and
> > perhaps Z axis blanking control). Many older systems did have such
> > displays -- the PDP-1 is a well known example (e.g. see Marc and Lyle's
> > CHM demo on YT[1]). Imlac PDS-1 is another. And before _digital_
> > systems, scopes or X-Y displays were a typical output medium for
> > _analog_ computers.
> >
> > For digital computers, output is point plotting, vector drawing, and/or
> > character generation depending on the sophistication (= cost) of the
> > hardware involved. You'd also need to find or write suitable software :)
> >
> > Yes, there were interface cards for PDP-11, such as AA11 (dual DACs).
>
> I made such a setup in college: we had an 11/20 with AA11 (and other lab
> I/O gear).  I hooked those up to the X/Y inputs of a scope, and a digital
> I/O line to the Z input.  Then loaded coordinate pairs into a buffer on the
> RC11 disk, which was set up to do DMA directly to the AA11 data CSR.
> Worked nicely, and with low overhead on a  machine that certainly could not
> afford to do refresh in software.
>
> The classic example of a computer display like that is the CDC 6000
> mainframe console.  That is essentially a pair of oversized oscilloscopes
> (with electrostatic deflection), with their X/Y inputs driven by a
> dedicated display controller that includes a vector character generator.
>
>         paul
>
>
>