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   What is Pterm and why do I need it?

Cyber1 runs on a mainframe emulation so you need a special terminal, or terminal emulator, to access it. Pterm is the terminal emulator program developed by Cyber1 staff, but there are others. Below are operating system releases for Pterm and others.

The original PLATO terminals were of several types:

  • Plato IV or Maggie. This is a "dumb" terminal by Magnavox which had the classic orange gas plasma display, a separate cabled keyboard, and used dedicated circuitry to provide the basic input and output for PLATO operations.
  • Plato V or PPT. This is an "intelligent" plasma terminal by Carroll which used a ROM "resident" for I/O featuring an 8080 processor. Many consider this terminal the pinnacle of original PLATO terminal design. It featured natural wood sidings for display case and its separate keyboard.
  • Information System Terminals (IST). Designed by CDC, there are three major subtypes.
    - IST-I. Using an 8080 processor it closely mimicked the PPT but used a CRT.
    - IST-II and IST-III. These terminals were designed as a single unit with integrated keyboard and used a Z80 and a RAM resident (downloaded from mainframe or loaded from flexible disk system).
    - 721/Viking. Using a faster Z80 processor with bank switchable RAM for larger resident programs, a green phosphor CRT, and separate keyboard, this was designed for both PLATO and other tasks.
  • Others. These are not the only terminals that were used to access PLATO, but they are the most common of the original equipment. There were many experimental terminals for early development of color displays and other hardware platforms.

Think of Pterm up to version 5.0.9 as a hybrid color PPT, and versions 6.0 and newer as a hybrid color IST-III. For the most feature-rich experience connect on ASCII port 8005, for "classic" protocol connect on port 5004. Note that port 8005 achieves faster perceived output vs. the "classic" protocol.

   Quick Q&A

Q: I have a real PLATO terminal (Maggie, Plato V, IST-I / II / III), and it powers up. Can I use it to connect to Cyber1?
A: Very possible. Due primarily to the efforts of one of our users - Aaron Woolfson - and drawing on the technical and social resources of the PLATO community, a small number of original PLATO terminals have been restored to working order and can connect to Cyber1 still today. A demonstration "classroom" was setup at the Computer History Museum for the "PLATO@50" conference held in 2010 (please see the links at the top of the page for photos). Some additional terminals were donatd by Aaron Woolfson to the Living Computer Museum in Seattle, where they do have a PPT on display for public access. Anyone who has a working PLATO terminal is invited to contact us for information on how to get your terminal connected to Cyber1. This might take some serious effort and time, and you will be the one doing all the research and spending all the time! But it can be done. Also, anyone who has a working terminal they might like to donate some preservation society such as the LCM are encouraged to do so.

Q: Are the Pterm binary and executable files safe to download? How can I be sure I am getting the authentic file?
A: Yes, they are safe to download. is 100% SSL secured to be sure that the information delivered over the web connection is safe and eliminates 'man in the middle' eavesdropping or even impersonation of our site. To take this a step further, our mainstream binary files (that is the Windows .EXE, Mac .DMG, Linux .RPM, and Linux .BZ2 files) all have a published SHA1 and PGP signature you can use to verify that they are the files we posted.

Q: My DNS service is broken and I cannot connect to Cyber1. How can I connect w/o DNS?
A: Occasionally we too have seen DNS errors. You can connect by using the static IP address ( of "". You can either pass command line arguments such as "pterm" , or you can use the Preferences page in Pterm to change the connection from "" to the static IP address

Q: What do I do if I run into a problem using Cyber1 or Pterm?
A: If you are signed on and having technical difficulties, use TERM-consult to get assistance or go to notesfile "ptermdev" and write a note. If you are not signed on, please use the Contact page and submit a report. The report will go via email to all members of system staff.

Q: I want to look at some of the programming that was written to create the games or other lessons I see on Cyber1. Why are so many closed and how do I get them to be opened for me to look at, or copy and use for myself?
A: If the 'inspect code' is closed, it is because the author wanted to protect their intellectual property. That might have been a decision made 40 or more years ago, but is still in effect, and we still honor that. We will, with express written permission of the author or authors, make a copy of a game or lesson and open that up to inspection to you. We are cautious in doing this and will validate any permission we receive from the author. Note, we will not provide you with contact information for any author as often we do not have it, but also it is our privacy policy not to release such information, period.
   Apple Macintosh OS X

Click to download PTERM-6.0.4.DMG. This is a disk image which contains a standard installer package. Click here to see SHA1 hash and PGP signature.
TIP: After download, double click the disk image, then double click the Install-Pterm package icon. This will install Pterm in the system Applications folder.

Q: What Mac OS versions are supported, and what processor architectures?
A: The stable version is good for Mac OS 10.5 or higher. The Beta and other new versions going forward will work on Mac OS 10.6 or later. We had some build issues with Power PC architecture for the 6.0+ releases and have decided to go forward with Mac OS 10.6 and higher as our lowest supported version for new development.

Q: Wait, what? Do you not have a PTerm for my older Mac? What kind of place is this?
A: Hang on, we do have older versions of PTerm available, going back to 2006 time frame. The most recent release that supports Power PC architecture is available here., PTERM-5.0.9.dmg. We are not completely daft after all!

Q: Are there any known issues with Mac OS and Pterm?
A: One potential problem is that Expose uses F9 and F10 (data and stop on PLATO). You can easily remap the keys used in Expose by going into 'System Preferences' and then clicking the Expose icon.
   Microsoft Windows

Click to download PTERM-6.0.4.EXE. This is a typical Windows installer package, just download/save first, then run. Click here to see SHA1 hash and PGP signature

TIP: Follow the instructions in the installer wizard.

Q: What versions of Windows does Pterm run on?
A: Tested and works with all versions of Windows since and including XP, including Windows 10, 8.1, 8, 7, Vista, and XP (both 32 and 64 bit varieties, we assume latest service pack of each version already installed).

Q: What about Windows 2000?
A: You will need run the previous build, Pterm 4.16. Why? The latest builds of Pterm do not work with Windows 2000 due to certain extensions Microsoft added starting with Windows XP. Our Windows build is compiled with Visual Studio.NET 2008 (C++) and does not generate binaries compatible with Windows 2000.


  • If you cannot connect, check firewall settings. Typical routers will permit outbound connections, but the default settings on some software firewalls do restrict outgoing traffic on unknown ports. So check ports 5004 and 8005 (color mode).
  • If you get the error "The program can't start because msvcr100.dll is missing from your computer. Try reinstalling the program to fix problem." then you need to download the Microsoft package that includes this component.
    Note: This is provided as a courtesy download, if you feel you'd prefer to download it from the Microsoft support site, please go and do so. You will need to search for the appropriate link.
    Microsoft Visual C++ 2010 Redistributable Package (x86)

   Unix (including Linux)

You have two options:

Click to download PTERM-6.0.4-1.I386.RPM. Click here to see SHA1 hash and PGP signature.
TIP: You can install that with yum which will also take care of any dependencies. It should work on any Linux for 32-bit or 64-bit Intel-style processors, Fedora 10 or later, or other Linux distributions that use the RPM package manager.

Currently awaiting build materials from development staff.

Click to download PTERM-6.0.4.TAR.BZ2. This is a b2zipped tarball of v6.0.4 containing the Pterm sources. Click here to see SHA1 hash and PGP signature.
TIP: Untar that, and see README-building.txt for detailed instructions. This approach should work for any Unix that supports wxWidgets and libSDL 1.2; FreeBSD, NetBSD, and others are known to do so as well as Linux.
TIP: If these don't work, you can check for an uploaded executable Pterm that fits your system from down below under the Member Contributions & Resources section. If you have tried and still fail to run, try again with X running.
TIP: Another possibility is to run the Windows version of Pterm 4.17 using Wine under Ubuntu 12.04 LTS. This is a fallback option for Linux users who may not want to take the time to build an executable native to their flavor of Linux.

   Member Contributions & Resources

If you downloaded the source for Pterm, have successfully compiled and tested the executable, and it is not already listed below, by all means please contact us to arrange an upload. Let us know exactly what OS and what hardware platform you built it on, and whether or not you are open to being emailed by a small number of potential users of your executable. No OS/hardware combo is too exotic for us.

Java Pterm v0.5, this is a long-term BETA. You will need the java runtime environment if you don't already have it installed. Source link here. Contributed by Tom Hunter (hunter/cfreaks).
Pterm for Sun Sparc, built on Solaris 9 with gcc-3.2.3, donated by Dave Dennis (dmd/cerl)
Pterm v1.12 for IRIX 6.5.26, built on an SGI Octane with gcc 3.3, contributed by Janet Clegg (janet/cbe)
Pterm v1.12 compiled on SuSe Linux 9.1 for x86, ponied up by Kurt Mahan (mahan/cerl)
Pterm v1.16 for Solaris 8, compiled with gcc 3.4.1, apportioned by Art Witczak (art/cerl)
Pterm v1.20 for Solaris 8, compiled with gcc 3.4.1, added by Art Witczak (art/cerl). He also supplied the diffs for Solaris 8.
Pterm v1.16 compiled under FreeBSD-5.3 for x86, given by Greg Becker (gbw/gondolin). He also supplied the diffs needed to compile on FreeBSD-5.3.
Pterm v4.1.11 for Fedora Linux 12 for x86_64, compiled with gcc 4.4.4, contributed by Jim Norris (norris/cerl).
Pterm v4.1.11 for Fedora Linux 12 for x86_32, compiled with gcc 4.4.4, contributed by Jim Norris (norris/cerl).
Pterm v6.0.2 compiled under Ubuntu 18.04 LTS, compiled with gcc 7.3.0, contributed by Mike Cochran (mike/s).

Pterm icon set, rendered in 3D and made available by Lisa Anne Allyn (Mimsy).
Download folder, this is a browsable starting point for all downloads mentioned on this page.

   Release Notes for Pterm v6

Major new capabilities thanks to Dale Sinder.

  • Added floppy drive emulation, using image files for the data. Two floppy units are supported.
  • Pterm now supports running MicroTutor programs, either downloaded from the PLATO host, or booted from floppy. The microprocessor emulation has been switched from 8080 to Z80. Emulation of the "terminal resident" is substantially more complete now, and includes terminal resident calls that were added after the CERL X-50 report and are documented in s0ascers.
  • The "connection" dialog is now a "new window" dialog, which lets the user select a pre-existing profile to use for the new window. The "preferences" dialog is now "edit profiles" and modifies a profile or allows the creation of a new one, without affecting the currently open windows. There is also a "session settings" dialog similar to the "edit profiles" dialog that allows changing parameters for the currently active window.
  • Profile handling has been cleaned up and made more consistent. A new window is created from a profile, which supplies the initial session parameters for that window. Those may be changed later (via "session settings") but that does not affect the profile itself.
  • Profiles (*.ppf files) are now stored in the application data directory rather than in unsuitable spots such as the directory where the Pterm application lives. That directory is OS-dependent:
    Windows XP:C:\Documents and Settings\<yourname>\Application Data\Pterm
    Windows Vista/7/8/10:C:\Users\<yourname>\AppData\Roaming\Pterm
    Mac OS:~/Library/Application Support/Pterm/
  • If you have saved profiles you want to carry over, copy them into that directory before starting Pterm. If the profiles directory is empty when you start Pterm, it will create two default profiles (which will appear in the connection dialog).
  • If you are interested in MicroTUTOR, how to configure Pterm Beta for emulated floppy disk usage, etc., please see MicroTUTOR with Pterm.