An Introduction to System Management

4.1 Operating instructions for the MDFS

SJ Research File Servers are designed to be run easily without the needfor much specialist knowledge. This section explains how the systemmanager should get going, setting up the communal filing system for allthe users.

This chapter is kept deliberately simple in order to explain theprinciples. System managers will find full descriptions of all thecommands and utility programs in Chapters 5 (user management) and 6(printer management).

If the File Server has not been installed for you, please refer toAppendix C which gives full instructions.

4.1.1 Switching on the File Server

The Modular Disc Filing System needs to be switched on at the front panelkey-switch; the green POWER light will come on. All the lights, except thered NO CLOCK light, will come on for two or three seconds while thehardware is tested (consult Appendix B if the system failure lightflashes). For normal operation, the switch should be turned to the SECUREposition. The yellow DISCS FREE light will flash after a few seconds --now insert all the floppy disks that you wish to use. There must be a copyof the File Server program on one of the disks at this stage, but it maybe on either a floppy disk or a hard disk; there is a copy on the disksupplied with the fileserver. Press the RELEASE DISKS button on the frontpanel, and the DISCS FREE light will flash more rapidly while the systemloads the program. After about ten seconds, the green ON LINE light willcome on and the DISKS FREE light will go out.

The fileserver is now ready for use. If you want to perform any systemprivileged user operations (for example, editing the password file orsetting the internal clock), then you should now turn the switch to theSYST position. More fundamental system operations such as formatting disksare carried out in Utility Mode, which is reached by either starting upthe fileserver as above, but with the key-switch in the SYST position fromthe beginning, or by typing *FINISH from a station on the network whilethe fileserver is running normally.

If, after the File Server is switched on, the RELEASE DISCS button is notpushed within thirty seconds the system will attempt to start the FileServer automatically.

4.1.2 Booting the File Server

When the File Server first comes on line it performs some consistencychecks on the discs connected and also builds a map of the free spaceavailable on the disks. On a system with a large amount of data this cantake several minutes. Until a disk has been successfully checked it is notpossible to write data to it. However, it is possible to read files asnormal. Attempts to write to a disk while it is being checked will resultin a Drive read only error. An indication as to how long thechecking process will take can be found by using the *FREE utility.The amount of used space on a disk is built up as the disk is checked andhence the values of bytes free and bytes used as displayed by *FREE willchange as the disk is checked.

If any error is found while checking a disk then the error will bereported on the system messages printer. The disk will stay in a ReadOnly state so that the possibility of damaging more data by writing tothe disk is eliminated. For more information on how to fix errors whichcause a drive to become read only see *DESTROY in chapter 4.

4.1.3 Switching off the File Server

Before switching off the File Server, press and hold in the RELEASE DISKSbutton on the front panel for about five seconds. The ON LINE light willgo out and after a short pause the yellow DISCS FREE light will comepermenantly on. Remove all the floppy disks and turn the front panelkey-switch to the STOP position - the front panel lights will extinguish.This operation will park the heads on any hard disk drives attached.

If the system is in the process of printing, it will stop when the RELEASEDISKS button is pressed; when the File Server is turned on again, previousprint requests will be remembered and restarted, going back to thebeginning of any uncompleted item in the print queue.

Do not switch off without pressing the RELEASE DISKS button, forexample using a master switch. (If a master switch is in use, then theFile Server should be run from a supply independent of it.) If the systemis not stopped before switching off, the cache memory may not have beenwritten back to the disks. In this case, it will probably be necessary torestore the system from a backup, as the data on the disks will becorrupted. It is also unwise to remove any floppy disks from the drivesbefore turning off the File Server, as power-off may have unpredicatableeffects on them.

If hard disks are fitted, we recommend not switching off the File Serverat all, since hard disks are considerably more reliable if they are keptspinning continously at all times. If your local Fire and Safetyregulations permit it, this is the best course.

4.1.4 Changing Disks

You may want to run a File Server system where there are more floppy disks(excluding backups) than floppy drives, and you insert them perhaps when aparticular class is present. This process is recommended only when yourEconet network extends only over a single room -- beyond that you will notnormally know who will want access to files as any time, so the onlycomplete solution is to have a File Server system large enough to have allfiles on line at all times.

The following procedure is necessary to change disks, either for thispurpose, or any other (eg to return to an earlier version of a disk).

Press and release the RELEASE DISKS button on the front panel. The FileServer may continue to access the disks for a few seconds, in order towrite back any information held in memory. When it has finished, the DISKSFREE light will flash alternately with the ON LINE light. While the systemis in this state, no File Server disks can be accessed by users. Removethe old disk(s), insert the new disk(s), and press the button again. Notethat it is not necessary to continue using the disc containing thefileserver program once the system is running - the program is retained inmemory.

When the disks are changed, the File Server will discard the old user listfor the changed disks (since the password file has probably changed). Thismeans that all users who are logged on from those lists will have to logon again - otherwise they will receive the error Who are you? ifthey attempt a filing operation. All opened files on changed disks will beclosed. Disks which have not been changed will be unaffected.

Do not change disks without pressing RELEASE DISKS and then waiting forthe DISCS FREE light. The system keeps information about the diskdata and transient information in memory. If you change a disk withouttelling the system, the vital root directory information will becorrupted, and it will almost certainly be impossible to access files onthe affected disks afterwards.

4.2 Organising the File Server

Your system will have a number of different users to whom you will want tobe able to give factilites to create files for themselves, to read certaincommunal files (for example library programs) and to have selective accessto other users' files.

The list of authorised users in a SJ Research File Server is kept in afile called the password file. This file can be read and saved onlyby someone with system privilege - normally only the system managerhimself and only when the front panel key-switch is turned to the SYSTposition. The password file contains information about each user: theirpassword, any accounts they have access to, and administrative informationconcerning start-up (boot) options, library directories and user rootdirectories.

If someone logs on to the syste, and their name does not appear in thepassword file, then they will be logged on as the default user, ifone has been set up by the system manager using EDITPASS (see Section4.3). If no default user has been set by the system manager, the user willreceive the error User not known.

When a user listed in the password file logs on, any password they quotewill be checked against the one in the password file before the log-on isallowed to proceed. They will then be given any rights and privilegeslisted against their name in the password file. The system will thensearch the disk on which the user's password file entry was found for theUser Root Directory specified for that user in the password file,which by default has that user's name, and will set this to be thecurrently selected directory (see Section 3.3 under *I AM for details). Ifno appropriately named directory is found, the disk root directory will beselected.

As described more fully in Section 3.3 (under *ACCESS and *ACCOUNT), theaccount(s) to which a user is given access control two things:

First, every file (or directory) has an account number, and if a userhas access to this account, then they are an owner of that file (ordirectory). Only an owner may create files in a directory, and only anowner may delete a file or change its access letters (see Section 3.3under the *ACCESS command). Note that there can be more than oneowner of a file (or directory), simply by allocating access to itsaccount to more than one user - this can be useful for communal files in aproject.

Second, each account has a credit balance of storage space, and anattempt to create a file which would cause that balance to become lessthan zero will be prevented, and cause the error Account bankrupt.

4.3 Command details

This section describes the operation of each of the commands and programsintended for use by the system manager for the day to day running of theFile Server system. Chapters 5, 6 and 7 explain in more detail how thesecommands are used for particular purposes.

These commands are not in themselves destructive in the wrong hands:provided that the system manager's password is kept secure, no other usercan actually change any of the settings, although some of the programsallow non-sensitive information to be read. In addition, the front panelkey-switch must be in the SYST position to enable the most sensitiveoperations.

The commands and programs documented here are:

*BACKUP Machine code program*CHECK Machine code program*CREDIT File Server command*DEBIT File Server command*DESTROY File Server commandEDITPASS BASIC programEDITPRINT BASIC program*FAST Machine code program*FINISH File Server commandFORCER BASIC programLISTUSERS BASIC program*LOGOFF File Server command*PGO File Server command*PSTOP File Server commandSETBACKUP BASIC programSETTIME BASIC programSETSYSTEM BASIC programSIZER BASIC programSYSADM BASIC program*TAPEINFO Machine code program


Basic program



Action with Wild Cards:

Not applicable


This program gives information on the use of accounts in the%PASSWORDS file. This is useful for checking that account numbershave not been doubly allocated and also for finding out which users own aparticular account number.

If the password file is large then it can take some time for the programto build the map of account numbers used. While this process is takingplace dots are printed on screen, one for every ten users in the passwordfile.



Scanning password files...

A. Summary of personal account
B. Full details of a single account
C. Users with no personal account
D. Summary of group accounts
E. Block accounts

F. Do all the above

G. Exit

Enter choice:

A will list all account numbers allocated as a personal account. Iftwo users share a personal account then both their User IDs will bedisplayed. If more than two users share a personal account then the firsttwo names in the password fil will be displayed plus the number of otherusers who own the account.

B will list all the users who own the specified account.

C will list all users who have not been allocated a personalaccount.

D will list the first user who owns the account number plus thenumber of other users who own the account.

E will list owners of the blocks of sixty-four accounts above&100.

F performs all of the operations A-E in sequence.

Likely Errors:

Key Locked - Error 5 (&05)
If the key switch on the front panel of the MDFS is not in the SYSTposition.

Insufficient privilege - Error 186 (&BA)
If the user does not have system privilege.

Compatibility Notes:

Not supported by Acorn systems

RISC OS Notes:ARCACCLIST is the RIS OS version.


File Server command


*CREDIT <account number> <amount> <diskname>

Action with Wild Cards:

Wild cards allowed in the disk name.


This command adds the specified <amount> in units of 1 kilobyte (K)to the balance of accounr <account number> on the specified disk.Account numbers range between 0 and &7FF and are in hexadecimal, butthe amount of credit is in decimal.

The maximum possible balance is 65535K, and the system manager mayeffectively turn off the space accounting system by setting all acountsthis much credit: 65535K is the largest single disk that can be fitted toa system.

System priveilege is required to execute this command.

The accounts system gives control of disk space filled by users' files.This command increases the allocation of space available for files withthe specified account number,

Note that the current credit balance of an account only represents thefree space available for files, and does not include files alreadyexisting in that account. It is therefore wise for the system manager tokeep a notebook containing details of users, their accounts and anysubsequent credit of debit given to them. A utility program SIZERis provided to find the total size of files in a directory tree, and thiscould be used to find the total space taken by a user's files at a laterdate.

The transient program *STATEMENT will give a printout of all theaccounts to which a user has access with the associated credit balance foreach. The system manager will normally have access to all accounts, and sowill get a long list of all accounts from 0 to 7FF for each disk in thesystem. It may be wise to send this output to a printer if all theinformation is required.


*CREDIT 89 512 Fuji1

allocates a further 512K to account number 89 on disk partition Fuji1.

Likely Errors:

Bad number - Error 4 (&04)
If there is not a number specified in both field or the number is in thewrong base (hex for the account number, decimal for the amount).
Key Locked - Error 5 (&05)
If the key switch on the front panel of the MDFS is not in the SYSTposition.
Insufficient privilege - Error 186 (&BA)
If the user does not have system privilege.
Syntax error - Error 16 (&10)
If the disk name is not provided.