FLP_SEC

Syntax	FLP_SEC level
Location	Gold Cards, Trump Card, SMS, THORs, SMSQ/E for QPC

The Gold Card, Trump Card and Thor range of computers, together with SMS provide a high standard of disk security, meaning that they are unlikely to fail to notice when a disk has been swapped over, and thereby try to write a file across two disks!

However, this level of security does affect the speed of disk access, as the system must check to see if the disk has been altered each time that it is written to.

The command FLP_SEC allows you to choose between three levels of security, the lowest of which (level 0) is still at least as secure as many other disk operating systems (such as MSDOS). The lower the level of security, the quicker disk access will be. The levels of security are as follows:-

Security Level 0

The disk system will only check to see if the disk has changed if a file is opened and the disk has stopped (ie. the disk light will have gone out) since the last time it was checked. The disk map is only updated when a file is closed (or flushed) and no other disk access has happened within half a second. Confusion can be expected on both read and write operations whenever a disk is changed whilst the disk light is still on or there are files open to the disk.

Security Level 1

The disk is checked each time that a file is opened, data is written to the disk, or the disk map is to be written; provided that the disk has stopped since the last time it was checked. The disk map is only updated when a file is closed (or flushed) and no other disk access has happened within half a second. The disk is not checked when anything is read from the disk, which can lead to confusion if a disk is changed whilst there are files still open.

Security Level 2

The disk is checked whenever a file is opened, data is written to or read from the disk, or the map is to be read or written to; provided that the disk has stopped since the last time that it was checked. The disk map and directory are updated and the slave buffers flushed every time that a file is closed (or flushed).

SMS NOTE

FLP_SEC has no effect - the security level is fixed at 2, the most secure.

SMSQ/E for QPC NOTE

FLP_SEC has no effect - the security level is fixed at 2, the most secure.