Contingency Planning for Systems

Contingency Planning for Systems

System Recourse

A system resource is any usable part of a computer that can be controlled and assigned by the operating system so all of the hardware and software on the computer can work together as designed.

Hardware and software need a way to communicate with each other, and they do so by using a combination of four system resources:

IRQ

Hardware devices use the IRQ bus on a motherboard to signal the CPU for attention.

Port addresses

Software addresses a hardware device using the devices port, or I/O, address.

The device “listens” to the bus to determine if it is being requested.

Memory addresses

Software communicates with physical memory located in either RAM or ROM chips using memory addresses.

DMA channel

Data travels back and forth between memory and a hardware device using this channel.

Resource Conflicts

Resource conflicts can manifest themselves in several different ways.

Some conflicts can be very easy to recognize; others can be extremely difficult to find and correct,

Here are some of the ways that resource conflicts manifest themselves.

Some of these may be consistent and repeatable, while others may be intermittent:

System hangs or lockups, particularly while using a peripheral device.

(Memory) parity errors on parity-enabled systems.

Noise or other problems from sound cards.

Junk being printed on your printer.

The mouse pointer hanging and refusing to move, or moving in a stuttering fashion.

Error messages from Windows 95, messages about the PC not operating at maximum performance, or the system dropping to “Safe Mode” or “MS-DOS Compatibility Mode”.

Errors and crashes of applications for no apparent reason.

Simple resolution for Resource Conflict