A computer
system including several nonconcurrently active hard disk drives ordinarily loaded with unique
software bundles. Each active hard drive introduces an especial
operating system setup and applications installation which is unconditionally denied access by activities obtained under another hard disk drive's
software instructions. An absolute isolation between two or more user's application programs and data files is achieved while sharing a common set of computer
system hardware and peripherals. Each category of nonconcurrent user operates independently without a
threat of corruption from activities of another prior or subsequent user utilizing the same computer
system for another disparate activity. In an IDE / ATA interface environment, a typical arrangement includes a setting of ROM-
BIOS to only recognize a MASTER drive with a subsequent user determined swapping of MASTER and SLAVE
modes between at least two hard drives utilizing a manual switch-over to obtain operation under
operating system and programs uniquely installed on each of the intently selected MASTER drives, while denying access to the alternant SLAVE drive. In an
SCSI interface environment, several drives set with the same
SCSI-ID number are selected between by manually controlling a completion of the
SCSI bus SEL line to the active intended drive and interrupting the SEL line to designated inactive drives.
Virus corruption of one primary drive is fire-walled against inadvertent transfer into an alternate primary drive thereby assuring system operating integrity for one user category in
spite of
virus contamination, command errors, or careless or malicious hacking introduced by another user category.