Dale - Computer Science Illuminated 390

Dale - Computer Science Illuminated 390 - 11.3 Disk...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Disk scheduling The act of deciding which outstanding requests for disk I/O to satisfy first 11.3 Disk Scheduling 363 Most operating systems allow the user to specify a set of paths that are searched (in a specific order) to help resolve references to executable programs. Often that set of paths is specified using an operating system variable called h’Lr , which holds a string that contains several absolute paths. Suppose, for instance, that user *! z (from Figure 11.5) has a set of utility programs that he uses from time to time. They are stored in the directory P‘!FzP*! z PR9D#D9Dz . When that path is added to the h’Lr variable, it becomes a standard location used to find programs that *! z attempts to execute. Therefore, no matter what the current working direc- tory is, when *! z executes the IxD 9,## program (just the name by itself), it is found in his utilities directory. 11.3
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/13/2011 for the course CSE 1550 taught by Professor Marianakant during the Fall '10 term at York University.

Ask a homework question - tutors are online