Skip to main content

(*) Knowing Your Machine

Unlike Windows, UNIX can be used by several users concurrently. In Other words, a single copy of the operating system software installed on just one machine can serve the needs of hundreds of users.

 These users could use dumb terminals or their own desktop PCs to access a central UNIX computer.


This computer will probably be located in a separate room with restricted access.

 If you are using a PC, then it must be configured properly before it can be used to connect to a  UNIX system. 

 Things are quite different, however, when you are using a WORKSTATION. This is a computer capable of producing high-quality graphics but meant to be used by a single user.

 Unlike the dumb terminal, a workstation has its own CPU, memory(the RAM--random access memory), hard disk, CD-ROM, mouse as a pointing device, and printer.

 Since it has all the things that UNIX needs, a workstation can run its own UNIX.

 Desktop PCs are also often referred to as workstations because there are versions of UNIX(like Linux) that can run on them.

 Even though workstations and PCs run UNIX and can be used in standalone mode, they are often connected to a larger, more powerful computer in the same way terminals are.

 There are a number of reasons you might want such an arrangement:

 (*) The central computer is administered properly, and you might want to keep all your valuable files there so they are backed up regularly.

 (*) You might like to use a powerful program that your workstation doesn't have but the central computer does.

 (*) All your incoming and outgoing mail is handled by the central machine, which may be your only link with the outside world, i.e., the Internet.

 Every workstation and PC provide a TERMINAL EMULATION facility that makes it abandon its normal mode and behave like a simple dumb terminal instead.

The workstation then doesn't use its own hard disk, CPU or memory for doing any work except providing the minimal resources required by the terminal emulation software.

The terminal emulation facility enables you to run a program on a remote machine using the remote machine's memory and CPU, and not your own.

Create a file in this mode and the file is saved on the remote machine's hard disk.

When you press a key, the computer generates a CHARACTER which represents the smallest piece of information that you can deal with.

It could be a letter, number, symbol or control sequence (like [Ctrl-fl]).

The string 10:20 pm contains eight characters (one for the space).

Every character is associated with a unique ASCII value(ASCII-- American Standard Code for Information Interchange).

The letter A has the ASCII value of 65, the bang(!) has the value of 33.

Both take up one byte(eight bits) each on your computer.

Many UNIX programs make use of these ASCII values.

Even though you may be completely familiar with the keyboard of your Windows PC, note that the functions of many of the keys change when the same PC doubles up as a UNIX or LINUX box.

The[F1] key doesn't invoke help and the [Delete] key may not always delete characters.

Moreover, every key has some use in UNIX.

When you see a symbol like ` (backquote)

you must be able to locate it easily on your keyboard (on the top-left), and not confuse it with ' (single quote),  because they have totally different functions.

LINUX : Using a combination of [Alt] and a function key, you can have multiple Virtual console or terminal sessions on a single PC. You can log in several times to the same computer, with  a separate "terminal" for each session. A single screen is shared by all sessions, which are accessed by using [Alt][F1],   [Alt][F2], etc.

Comments

Post a Comment

Popular posts from this blog

(*) Logging In and Out

The good old dumb terminal connected to the computer's serial port was once the only means of connecting to a UNIX system. Later, the TELNET program became popular for connecting in a network.  For security reasons, the TELNET facility could be disabled on your system and the SECURE SHELL( SSH ) could be the only means of connecting to a remote UNIX box. In that case, UNIX and LINUX users can use the SSH command if available. Windows users may use PUTTY or any of the free SSH programs available on the Net. If you are using a workstation or desktop PC running Linux, then you can log in directly.
Post a Comment
Read more

(*) The system Administrator

On a large system serving hundreds of users, someone has to be given charge of administration of the system.  This person is known as the system administrator . The administrator is responsible for the management of the entire setup. She allocates user accounts, maintains file systems, takes backups,manages disk space and performs several other important functions. She is the person to be contacted in case of a genuine problem. If you own a workstation or PC that runs some flavor of UNIX, then you are probably its administrator . You are then directly responsible for its startup, shutdown and maintenance. If you lose a file, it's your job to get it from a backup. If things don't work properly, you have to try all possible means to set them right before you decide to call a maintenance person. You can use a UNIX machine only after the administrator has opened an account with a user-id and password for your use. These authentication parameters are maintained in two separate files...
Post a Comment
Read more

(*) The UNIX operating System

There have been many operating systems in the past, one at least from each hardware vendor. They were written in a near-machine language known as ASSEMBLER. The systems were proprietary( relating to an owner or ownership or  (of a product) marketed under and protected by a registered trade name .)  because assembler code developed on one machine wouldn't run on another. Vendors required consumers to purchase expensive proprietary hardware and software if two dissimilar machines needed to talk to each other. Ken Thompson and Dennis Ritchie changed all that forever. They created UNIX . This UNIX operating system marks a strong departure from tradition.It has practically everything an operating system should have, but also introduced a number of concepts previously unknown to the computing community. Beginners with some experience in Windows think of UNIX in terms of it, quite oblivious to the fact that the similarities are only superficial. UNIX is way ahead of othe...
Post a Comment
Read more