ZOC is a professional and feature
is a professional and feature rich terminal emulator that lets you access
character based applications server computers, mainframes and other devices,
using terminal emulations like
In the early days of computing when processors and memory were extremely expensive,
companies would often purchase one large, powerful central computer. This computer
was shared by many users, who accessed it through so-called dumb terminals
(sometimes they are also called thin clients or simply terminals).
These terminals enabled the users to enter and view data, whereas the actual processing
was done by the central computer. The terminals (thin clients) were devices which consisted
of a screen, a keyboard, and the technology that allowed them to transmit keystrokes to and
receive output from the server, but had no noteworthy computing power of their own.
In recent years, the client/server concept and central computing has undergone something of a
renaissance. As a direct result of this the necessity of using a terminal to access a computer
located in a remote location (be it somewhere across the globe or server vault in the basement
of the same building) is yet again receiving a lot of attention, in spite of having been
put aside and deemed a thing of the past.
Terminal Control Codes
As noted above, a terminal initially was a combination of keyboard and a screen which
were connected to a remote computer through a network, modem or network.
However, to allow the server programs some flexibility, the terminals had some limited
computing power that enabled them to perform tasks beyond merely printing all received text.
Instead, they could receive specific codes which were embedded in the text, and use
these to format the output of the text, rather than just printing text left-to-right and
top-to-bottom like a teletype.
However, each manufacturer (e.g. IBM, Digital Equipment, Wyse Corp.) invented different
codes to perform the formatting of text, so the terminals to access a certain type of
server needed to be bought from the manufacturer of the server.
In other words, different manufacturers used different codes that the servers sent to the
terminals in order to move the cursor, change the color, clear the screen and so on.
Among the best-known terminal manufacturers were DEC (who created the
line very popular of VT-Terminals, including vt100,
vt220 etc.) and IBM
and 5250 terminals).
There were also attempts to standardize codings for these tasks, the so-called ANSI terminals.
Emulate Terminals on Personal Computers
As processors and memory gradually became more affordable, the idea of a Personal Computer was born.
This novel concept meant that each user would be able to access their own memory, and that their
personal processor would be sitting right there on their desk.
As the use of computers has increased, data processing has once again become very demanding.
Nowadays, it is not uncommon to need to access gigabytes of data in databases or to process
extreme amounts of information. Because of this, the idea of server computing has been resurrected.
Personal computers with memory and processors are still used for simple computing tasks such as
word processing, but for more complex work users may need to access remote systems. Returning to the
use of dumb terminals would be impractical - few people would have room for another keyboard and
screen on their desk. Instead, software now plays the role of a dumb terminal. This software is
called a terminal emulator, as it emulates a dumb terminal or thin client on a PC.
Benefits of Terminal Emulators
In short, a terminal emulator is a program that does what a dumb terminal used to do in the early
days of computing. It transmits keystrokes to the remote server, receives output from the server,
and displays it in a window which simulates the screen that was used in the past. However, the
real benefit of using a terminal emulator is that it really isn't as 'dumb' as a real terminal.
Instead, it offers functions such as logging output to a printer, saving output to disk, allowing
input and output to be sent/received and processed automatically. A terminal emulator can also
help you automate repetitive tasks.
As noted above, many manufacturers used to develop their own terminals with their own type of
ommunication between the server and the terminal. The good thing about modern terminal emulators
is (compared to hardware terminals) that they can understand most of the codes that were used
in the past. A single terminal emulation program like ZOC can actually play the role of both an
IBM and a DEC terminal, depending on which server a user needs to access (e.g. an IBM mainframe or a Unix server).
Who uses Terminal Emulators?
Nowadays, terminal emulators are used for a wide variety of different tasks. They are used by Unix and
Linux administrators to access their web servers, by employees of companies who need to access different
types of software on central computers, by doctors to retrieve blood test results from central lab
computers, and so on. In short, anyone who wants to access any kind of data on a central computer
needs a terminal emulator.
The ZOC Terminal Emulator is a professional terminal emulator because
it supports the standards of several manufacturers (vt100, vt220, xterm, TN3270, Ansi, Linux/Xterm,
Wyse, to name just a few), and allows users to access virtually any server that requires the use of a
terminal or terminal emulator. As well as the basic terminal functions, ZOC offers a wealth of additional,
useful features. This terminal emulator takes advantage of the computing power of a PC to allow you to
automate tasks (such as logging on or retrieving data automatically), log sessions on screen or file
(for documentation or later review), copy data between a text processor and the remote server, and much