Реферат: DOS And Unix Essay Research Paper Compare

hard drive, printer, modem, etc. is seen as a file. Thus, access to any device

is carried out as access to a file. This is possible through the fact that UNIX

differentiates between kinds of files. In fact, the processes themselves are

seen as files, which permits the establishment of another important UNIX

characteristic, interprocess communication. 5. Virtual Memory The fact that UNIX

has virtual memory allows the number of processes being executed to require more

memory than exists in the machine. 6. Graphic Interface Although not exactly a

novel characteristic of UNIX, most versions now have a graphic interface. 7.

Interplatform Support This is another characteristic that was added to UNIX

which lends the capability to execute programs from other platforms (DOS and

Windows), within the UNIX environment. 8. Networks The usual UNIX communications

protocol is TCP/IP. This allows variants of UNIX based operating systems to

communicate between themselves or with other platforms (Osiris, 1-2). CONTRAST

Both DOS and UNIX present a number of similarities, several of which shall be

addressed here. First, both systems are interactive, meaning that the shell

presents a prompt and waits for the user to enter a command. After the return or

enter key is pressed, the shell processes the command and when the command is

finished, the shell re-displays the prompt. Second, DOS batch files and UNIX

script files can be used which can store commonly used commands in a file, which

when executed, runs each command as though it has been typed from the command

line. A sequence of commands can be executed by executing the file which

contains the command(s). Third, the handling of files in both DOS and UNIX is

simplified by using wild-card characters to match files which match particular

patterns. Also, with both operating systems, users can customize and control the

behavior of the shell by using special variables that the shell supports, such

as the prompt (20,1). In addition, both systems make use of ?pipes? whose

symbol is a vertical bar ( | ). With this convention, the output from one

command becomes the input for another command. Several dissimilarities are worth

noting. As was previously mentioned, DOS is a single user, single task operating