<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Feb 3, 2018 at 8:12 AM, Pär Moberg <span dir="ltr"><<a href="mailto:ghostdewolf@gmail.com" target="_blank">ghostdewolf@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><span class="gmail-m_-7596185667179402943gmail-">On 03/02/2018, Bob Eager <<a href="mailto:rde@tavi.co.uk" target="_blank">rde@tavi.co.uk</a>> wrote:<br>
> On Sat, 3 Feb 2018 11:41:38 -0000<br>
> "Dave Wade" <<a href="mailto:dave.g4ugm@gmail.com" target="_blank">dave.g4ugm@gmail.com</a>> wrote:<br>
><br>
>> > -----Original Message-----<br>
>> > From: Simh [mailto:<a href="mailto:simh-bounces@trailing-edge.com" target="_blank">simh-bounces@trailing-<wbr>edge.com</a>] On Behalf Of Pär<br>
>> > Moberg<br>
>> > Sent: 03 February 2018 02:26<br>
>> > To: <a href="mailto:simh@trailing-edge.com" target="_blank">simh@trailing-edge.com</a><br>
>> > Subject: [Simh] PDP for beginners<br>
>> ><br>
>> > I am looking to put up a PDP-# machine to play with. What machine<br>
>> > and OS should I use. I am looking for simple/beginner system, or as<br>
>> > beginner it got.<br>
>><br>
>> I think I would start with a PDP-8. NO telnet terminal. Simple OS,<br>
>> lots of software and support. If you want blinken lights try one of<br>
>> these:-<br>
>><br>
>> <a href="http://obsolescence.wixsite.com/obsolescence/pidp-8-get-one" rel="noreferrer" target="_blank">http://obsolescence.wixsite.co<wbr>m/obsolescence/pidp-8-get-one</a><br>
>><br>
>> its SIMH with a nice panel<br>
><br>
> I was going to suggest the same thing. Be warned that there's quite a<br>
> lot of soldering in a PiDP-8 - although not as much as an SBC-6120! (I<br>
> have both)<br>
<br>
</span>Why I want terminal support is so I can use some of my old clunkers as<br>
terminals and access the server from different places in the house.</blockquote><div><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font color="#0000ff">Like others the PDP-8 is definitely were I would start because there is so much around for it, from single user, batch and timesharing systems. </font><font color="#0000ff" face="arial, helvetica, sans-serif"><div class="gmail_default" style="display:inline"> Google is you friend of </div>course<div class="gmail_default" style="display:inline">, a couple of interesting URLs are: </div></font><a href="http://bitsavers.trailing-edge.com/pdf/dec/pdp8/">Bitsavers's PDP-8 Download</a><font color="#0000ff">,</font><div class="gmail_default" style="display:inline"> </div><a href="http://bitsavers.trailing-edge.com/pdf/dec/pdp8/handbooks/" style="font-family:arial,sans-serif">PDP-8 Handbooks</a>,<div class="gmail_default" style="display:inline"> <a href="https://raymii.org/s/articles/Running_TSS_8_on_the_DEC_PiDP-8_i_and_SIMH.html">Running_TSS_8_on_the_DEC_PiDP-8_i_and_SIMH.html</a><font color="#0000ff">, and</font> </div><div class="gmail_default" style="display:inline"><font color="#0000ff"><a href="http://www.pdp8.net/index.shtml,">PDP-8 Net</a>.</font></div></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><div class="gmail_default" style="display:inline"><font color="#0000ff">[BTW: do not pass go .... down load the PDP-8 users handbook to start BTW].</font></div></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font color="#0000ff"><br></font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font color="#0000ff">There are also a number of different simulators to work with. But there are some caveats that have been discussed (more in the minute). I too have a PiDP-8 and I have it connected to serial ports on the RPi to drive physical connections, but you can use the telnet stuff from simh described elsewhere.</font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font color="#0000ff"><br></font></div><div class="gmail_default"><font color="#0000ff"><font face="arial, helvetica, sans-serif">That said -- as much as I love Bob Supnik and Mark Pizzolato's wonderful simulation system (particularly if you want to talk to 'real hardware'), if you want to to learn a but more about the PDP-8 itself, I might recommend you also consider </font></font><span style="color:rgb(0,0,255);white-space:nowrap">Berhbard Baehr's amazing PDP-8/e simulator for the Mac: </span><span style="color:rgb(0,0,255);white-space:nowrap"> </span><a href="http://www.bernhard-baehr.de/pdp8e/pdp8e.html" target="_blank">A PDP-8/E Simulator for the Apple Macintosh </a>. <span style="color:rgb(0,0,255)">A know a of a couple of excellent CS Departments that use this emulation to teach their students in their intro to architecture class because it gives also exposes some more modern debugging schemes and thus is easier to get a handle on what is going on 'inside.' From the web page:</span></div></div></div><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div class="gmail_extra"><div class="gmail_quote"><div class="gmail_default"><p style="font-family:"Lucida Grande",Geneva,Verdana,Arial,Helvetica,sans-serif"><font color="#ff0000">The simulated machine is a PDP-8/E with 4K words of memory and optionally a KM8-E Memory Extension (with up to 32K words of memory) and a KE8-E Extended Arithmetic Element. I/O devices are implemented as plugin modules, and plugins for an ASR 33 Console Teletype, an ASR 33 Auxiliary Teletype, a PC8-E High Speed Paper Tape Reader and Punch, and a RK8-E Disk Cartridge System are available.</font></p></div></div></div><div class="gmail_extra"><div class="gmail_quote"><div class="gmail_default"><p style="font-family:"Lucida Grande",Geneva,Verdana,Arial,Helvetica,sans-serif"><font color="#ff0000">There is also a KC8-EA Programmer's Console plugin enabling the user to operate the simulator (nearly) like a hardware PDP-8/E, including single step execution on memory cycle level.</font></p></div></div></div></blockquote><div class="gmail_default" style="display:inline"><font color="#0000ff"><font face="arial, helvetica, sans-serif">As other have pointed out OS/8 is out there which like the later DOS/11 and RT-11 which we modeled on it, is basically single user. But there is also TSS/8, ETOS and I think a few other </font></font></div><font color="#0000ff" face="arial, helvetica, sans-serif">multi-<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">user systems for the 8. But I would recommend starting with DOS/8. I used's OS/8 and TSS/8 'back-in-the-day.'</div></font><br><div><font color="#0000ff" face="arial, helvetica, sans-serif"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><br></div></font></div><div><font color="#0000ff" face="arial, helvetica, sans-serif"><div class="gmail_default" style="display:inline">That said, if you do want to mess with these with real hardware such as PiDP-8, there is an interesting feature/bug that is annoying when working with the DOS/8 (or TSS/8) under emulation on a real-terminal (on an XTERM or the like this is less of an issue). It's how the hardware works and how ^S/^Q flow control is implemented in the old systems. The problem is that the way the OS works for terminal output is that spins on a read bit from the UART before it writes the next character. This is done at the lowest level of the OS. In the old days, even at the 'slow' 10cps of an ASR-33, the truth is the simulated hardware will push the next chars out faster than you the human can respond. The ^S you will send back to the emulated system will be seen much, much later that it would have been in the real HW. [The solution is we need to change simh to not set the ready bit until a real time amount of 10 cps for 110 baud or 960 cps for 9600 baud - but this is very hard to do and in practice, not needed because we mostly use simulated TTY today]. i.e. </div></font><span style="font-family:arial,helvetica,sans-serif"></span><font color="#0000ff"><font face="arial, helvetica, sans-serif">If you are one a simulated TTY such as xterm, there is enough buffering in the xterm</font><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> software emulation to not 'lose' character and then it adds </div><font face="arial, helvetica, sans-serif">the ability to 'scroll back</font><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">.</div><font face="arial, helvetica, sans-serif">'</font><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> B</div><font face="arial, helvetica, sans-serif">ut on a real display of the day, you might out of luck</font><div class="gmail_default" style="display:inline"><font face="arial, helvetica, sans-serif"> (i.e. when I connect even as modern a terminal as an Heathkit H19 or a Wyse-60)</font></div><font face="arial, helvetica, sans-serif">.</font></font></div><div><font color="#0000ff"><font face="arial, helvetica, sans-serif"><br></font></font></div><div><font color="#0000ff"><font face="arial, helvetica, sans-serif"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">Best of luck,</div></font></font></div><div><font color="#0000ff"><font face="arial, helvetica, sans-serif"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">Clem</div><br></font></font></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font color="#0000ff"><br></font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font color="#0000ff"><br></font></div><br></div></div><div hspace="streak-pt-mark" style="max-height:1px"><img alt="" style="width:0px;max-height:0px;overflow:hidden" src="https://mailfoogae.appspot.com/t?sender=aY2xlbWNAY2NjLmNvbQ%3D%3D&type=zerocontent&guid=b26f2414-fc64-49d6-9f24-14a75d449817"><font color="#ffffff" size="1">ᐧ</font></div>