CANCELLING AND CORRECTING COMMANDS
2.9 FILES AND PARTITIONS r OVERVIEW
This section will provide a general over-view of files, partitions, and drives. It is
intended for those new to the HiNet system who may be unfamiliar with these terms. Additional information on files will be found in section 2.10 and detailed information on how partitions are used with HiNet will be found in section
2." .
FILES.
All computer work is stored in files.
Almost everything you do with your workstation will in some way concern files--taking
information out of a file, putting information in, using one file to process another, and so forth. Like a paper file, a computer file can range in size from very long to very short and contain almost any kind of information. There are two general types of computer files--data files and program files.
Program files (often called 'Applications Programs') tell the computer how to carry out your instructions. Programs are the tools you and the computer work with. Word processing programs are used to write documents and letters, accounting programs keep books, data base management programs analyze data, and so on. Applications programs such as these are usually purchased or custom-written by professional programmers.
Data files are created by your use of applications programs. They are the files that contain your work. The individual memos and manuscripts written with a word processing program are stored as data files, as are the ledgers created and maintained by an accounting program, or the mailing lists maintained by a data base management program.
PARTITIONS.
Your workstation is connected to a Master Computer that uses a Hard Disk Memory to store information for everyone on the network. This Hard Disk Memory is divided into Partitions that contain files. You can think of the Hard Disk Memory as a very large filing cabinet with dozens of drawers. Each partition is like a separate file drawer that contains many or few files.
Partitions may be assigned to specific people, to departments, or to general functions.
For example, a partition named 'ACCOUNTS' might
be used by many people and contain accounting programs, ledgers, customer files, and tax records (all in separate files). A second
parti tion labeled 'MELVIN' might be used by one person to keep his personal work, while a third named 'SYSTEM' could be used to store various programs that everyone on the network shares.
When you tell the computer to save some work that you have done on your workstation it is placed in a file. You have to name the file to be used and the partition where the file is kept. I f you change the contents of a file and order the computer to save it, the old version will be erased and the new version placed into the file. Some applications programs will rename the original file and save it as a backup file.
DRIVES.
Inside a DMS workstation are 4 connections, each of which you can link to one of the parti-tions on the Hard Disk. In computer terminology these links are called 'Drives' or 'Logical Devices', and they are labeled 'A', 'B', 'e' and
'D' •
Using the ASSIGN command (see section 2.11.5) you can electronically connect each of your drives to one specific partition on the Hard Disk. In other words, your workstation can be linked to any four of the partitions on the Master Hard Disk.
Assigning a partition (file drawer) to one of your drives gives you the power to open that parti tion and work wi th its contents. You can read material from the files stored in the partition, alter them, erase them, create more files, rename old ones or copy them to other partitions.
NOTE---The label 'Drive' can be associated with any memory storage device (Hard Disk
partition, Floppy Disk, etc.) depending on how you assign it. For example, your network may contain some workstations equipped with Floppy Disk Drives (the DMS-3/F, or the DMS-3/F, for example). At those stations you can assign one of your four network drives to a Floppy Disk Drive or a Local Hard Disk partition instead of a Master Memory Hard Disk partition.
PARTITIONS
B B GJ ~ [:;;J GJ G
G;] [;;J c::;;] g
~ G;J ~ ~
r:;;] [:;;] [;;]
r:::;;:] [::;;]
=
c;;] GJ
2.10 FILES.
Programs and data are stored in files. Like a file drawer, each partition may contain many files. Once you are logged onto the system and accessing the proper partition, most of your work will concern files.
2.10.1 FILE NAMES.
Every file, whether program or data, has a distinct name by which you and the computer know it. When you create a file through the use of a program, you will give it its name. Files can also be renamed at any time.
File names follow a simple pattern--first an identifying name of 1 to 8 characters, then a period, and then a 'type' name of 1 to 3 charac-ters which is used to identify what sort of file it is, for example: SHOPPING.LST, CHAP-3.TXT, WHO.COM, LETTER.BAK etc.
2.10.2 FILE TYPE IDENTIFIERS.
The period and three-character file type identifier at the end of a file name are not mandatory; XX, 2, and ADVERT could all be used as file names if you wish. However, most people find it useful to identify files by their kind, both for their own information and because some operations (erasures, for example) can be per-formed on groups of files rather than one by one.
By common convention some type identifiers have standard meanings. For example: .COM, .CMD, .BAS and .OVR usually indicate a program • .BAK
indicates a backup file (such as those created automatically by some word processing programs) •
• TXT usually stands for Text, .DOC for Document, .LST for List, and .LTR for letter.
2.10.3 FORBIDDEN CHARACTERS.
You can name (or rename) a file anything you want as long as there are no more than 8 characters before the period, no more than three after, and you do not use any of the 1 4
forbidden characters:
> < , ; :
+ ?* ] [) ( .
and TAB. (These characters are reserved for special CP/M instructions. E.g., the period is used as a file separator.)
To learn how to rename a file see sections 3.4. and 3.6. To learn how to erase a file see section 3.5. To learn how to copy files from one parti tion to another see section 3.6.
NOTE---Make sure you do not give two different files the same name. Even if they reside in two different partitions, the chance of confusing them ca lead to one or both files being destroyed. CP/M will not allow you to have the same filename twice in one partition. If you copy a file into another partition that has a file with the same filename, the file in the destination partition will be overwritten, effectively erasing it. Program files normally exist in several different partitions because
they have the exact same content.
2.10.4 FILENAME WILDCARD SYMBOLS.
When listing files for certain commands (ERASE, for example) you can identify a group of files by using the characters that their names have in common plus the wildcard symbols * and
?, to stand for those characters that are different. A question mark will stand for any single character, and an asterisk will stand for everything on one side of the period.
? stands for ANY SINCLE CHARlCl'ER.
* stands for EVERr1HIY:; ON ONE SIDE OF 'mE PERIOO.
For example, FI??DOC would represent any file with FI as the first two letters of its name, any additional two letters, and DOC after the period (FISH.DOC, FILM.DOC, FIRM.DOC, etc).
*.LST would stand for any file of the type .LST (SHOP.ISl', MAILIt«;.LST, POOBAH.LST, R2D2.LST, etc). Since
*
stands for everything to one side of the period *.*, would stand for every single file in a partition.DIRECTORY.
To see a directory of the files contained within the partition you are currently accessing
(that is, the partition assigned to the drive you are logged onto), type DIR after the command prompt (A)DIR). For more on Directories see sections 3.2 and 3.3.
2.11 PARTITIONS.
2.11.1 PARTITION NAMES.
Each partition on the Network's Hard Disks has been given a name. Some may be given the names of the people who use them for their own work. Such names may be the same as their System User Name. A System User Name, remember, allows a person to login to the HiNet network; it is like a key allowing you access to the HiNet system. A named partition is somebody's assigned workspace.
Other partition names might identify the partition's contents (Ledgers, Forms, Inventory) or the department that uses the partition
(Sales, Personnel, Research). Usually the partition named SYSTEM is used to hold all of the programs used by everyone on the network.
WARNIM;! You should never erase, change, or a&l anything to the SYS"l.'EM partition (or the
srsrEM
partition's files) without first discuss-ing it with the person in charge of the network.2.11.2 DIRNET (DIRECTORY NETWORK).
Type the command DIRNE'l' (A>DIRNET <CR».
This stands for 'Directory of the Network.' Your screen will now show a listing of all the parti-tions on the Hard Disk. The screen will display a table similar to this:
A>DIRNET <CR>
DIRNET Version x.x
Partitions on VoLume 0 voLm1astr
SYSTEM 2M bytes CHOU 1M bytes MRS G 512K bytes ACCOUNT1 1M bytes ACCOUNT2 2M bytes MARY2 512K bytes LEROY 512K bytes MELVIN 2M bytes PERSONNEL 1M bytes RESEARCH 2M bytes
2.11.3 PARTITION SIZES.
When you look at the DIRNET directory you can see that each partition name is followed by a number. This gives the partition size in thousands of bytes. A byte is one character or space in written text, and an average single-spaced typed page is about 3,000 bytes, usually abbreviated 3K. The K stands for 'Kilo' (the metric word for thousand). A million bytes would be abbreviated 1 M (M for 'Mega').
The size of each partition is determined by the person in charge of the network. The
partition's size determines the number and size of the files that can be stored within a given partition. Thus, if you had a S12K partition, you could put into it one file of 512,000 bytes, or any combination of files that added up to no more than 51 2K.
2.11.4 PARTITION DEFAULT ASSIGNMENTS.
The person in charge of your network assigns specific partitions to some or all of your drives as 'default partition assignments'.
Whenever (and wherever) you log onto the network, your default partition assignments will automati-cally be in effect. Thus, if your default parti-tion assignments were:
A: SYSTEM