C-Kermit 5A(191) processes incoming data in parallel with screen updating. Furthermore, the screen is now updated far more efficiently than before. To give an idea of the speed improvement, we used a ripple-test benchmark that scrolls 1000 80-column lines of text, obtaining the following display timings for various TELNET clients attached to a 10 Mb/sec Ethernet network running on the same PC in a fullscreen session:

  C-Kermit 5A(190)    24 sec
  IBM Telnet          22 sec  (TCP/IP 1.2.1)
  MS-DOS Kermit       12 sec  (v3.14 under DOS, not under OS/2)
  C-Kermit 5A(191)     5 sec

The new display management model has also been used to accomplish several other astounding feats:

• Terminal sessions remain active behind popup help screens.
• Incoming material is processed even when screen is rolled back.
• Copy-and-paste can span multiple screens (more about this below).

Meanwhile, serial port handling is now far more efficient, putting less load on the CPU, allowing serial-port input/output to take place at high speeds without seriously impacting the rest of the system.

In Warp window sessions, C-Kermit now supports any combination of screen height and width, up to 255 columns and 254 rows with a maximum screen area of 8192 characters.

In fullscreen sessions the terminal screen can now use 40, 80, or 132 columns and 24, 42, 49, or 59 rows. Not all combinations are supported by all video hardware. Warp is not required.

Host-directed screen-width switching in VT100, VT102, and VT220 emulation is now implemented for 80-column and 132-column modes when the video adapter supports it. Screen dimensions are automatically reported to the host on TELNET connections if the TELNET server supports (and uses) the "NAWS" option.

• The Microsoft Russian DOS keyboard layout.
• Hot-key switching between Russian and English modes.
• Automatic translation to the host character-set (KOI, ISO, etc).

This is in addition to the keyboard methods that were already available in earlier releases:

• A Compose key for Latin-1-like character sets (for Western European languages like Italian, Portuguese, Norwegian, German, French, etc).
• A Hebrew keyboard mode for Hebrew and Yiddish.

• Text selection can now span the entire virtual screen, scrollback buffer included.
• You can reassign these functions to different mouse events.
• You can assign them to keys.
• You can assign keyboard verbs, macros, or text to mouse events.
• Copy-and-paste works consistently between C-Kermit and other apps.

To get a quick idea of the power of the new "mark mode": after installing the new version, starting it up, and accumulating a bunch of screens in the rollback buffer:

• Hold down the left mouse button.
• Drag the mouse towards the top of screen, watch text being selected.
• Now drag it PAST the top of the screen -- watch what happens.
• Push the Arrow, Page Up/Down, or Home/End keys while dragging.

Any text that you select this way can be copied to the PM clipboard, printed on your printer, copied to a file, or pasted directly into your terminal session.

Incoming TCP/IP connections are now accepted -- you can TELNET to OS/2 C-Kermit on a pre-arranged socket and have a "chat" session or execute Kermit server functions.

OS/2 C-Kermit can now dial your Warp IAK SLIP connections for you, using a special technique to "borrow" the serial port from the SLIP driver. This gives you a lot more flexibility than you get with SLIPTERM.

There are new controls for TELNET NVT/binary mode and CRLF mapping, since these areas are so problematic with the proliferation of incompatible (and often confused) TELNET servers:

  SET TELNET { NVT, BINARY } NEWLINE-MODE { ON, OFF, RAW }
  SET TELNET BINARY-MODE { ACCEPTED, REFUSED, REQUESTED }

SOCKS support added for TELNET'ing through firewalls.

...include:

• Improved context-sensitive help screens, status lines, and messages.
• More key combinations are recognized for SET KEY.
• System Sounds can now be used to differentiate "Information", "Warning", and "Error" events.
• REMOTE RENAME and REMOTE COPY (both ends) added.
• Various other new commands, bug fixes, cleanups, etc.

DOCUMENTATION

If you will be using OS/2 C-Kermit and you have not already purchased this book, please purchase it. It will answer your questions, it will show you how to get the most out of the software, and book sales are the primary source of funding for the Kermit effort.

Your serial communication package MIGHT enable you to connect to your host this way, but if it works right throughout your session, it's pure luck. Numerous items -- echoing, screen size, terminal type, and other parameters -- need to be negotiated and sometimes changed dynamically throughout the session, depending on the service and the server.

A serial communications program is not designed to handle this type of work. So the virtual modem software must handle the TELNET protocol parameter negotiations on behalf of the communication software. So far, so good. The problem is that when things change, the virtual modem software has no way of telling the communications software, and similarly, when the user changes things in the communications software, the virtual modem doesn't find out about it and can't tell the TELNET server.

To complicate matters further, the TELNET Network Virtual Terminal (NVT) definition does not work like the ASCII terminal that your serial communications software is emulating. Certain characters must be handled specially, including carriage return, linefeed, and the "all-ones" character, hex FF. Furthermore, special items like the BREAK signal must be handled by special TELNET protocol messages.

So when using serial communications software to accomplish a TELNET connection over a virtual modem, you are very likely to experience all sorts of problems, including:

• Terminal-type and/or screen-size mismatch.
• Faulty echoing: characters can fail to echo when you type them, or might echo twice. "Password silencing" might not work.
• You might get overprinting or a "stairstep" effect as the host sends lines to your terminal screen.
• Carriage return (Enter) might have no effect at all when you type it.
• A carriage return might result in two blank lines.
• The session might suddenly hang because a special character has not been properly escaped during terminal emulation or file transfer.
• BREAK, required by some hosts and applications, can't be sent.
• When things go wrong, you have no effective debugging tools at your disposal, and even when you can diagnose the problems you often have no way to fix them.

THE MORAL: If you want a fully-functional and dependable TELNET session, use a real TELNET client. If you want to use the same software for both serial and TELNET connections, try C-Kermit.