Microsoft Corporation - A+ Certification Training Kit

The following points summarize the key concepts in this chapter:

ROM and RAM

• ROM is a form of nonvolatile memory that is used in PCs to hold POST commands.
• RAM is the memory that is used by the CPU to temporarily hold data that is currently used by the system. It is cleared any time the system is powered down or rebooted.
• RAM chips come in many sizes and shapes. It is important for the computer technician to be able to identify the different types and calculate how many chips, banks, or rows of memory modules are needed to upgrade a computer.
• The number of SIMMs required is based on the width of the data bus.

Mapping Memory

• Memory (RAM) is allocated to different parts of the CPU. A computer technician uses a memory map to describe how memory is allocated.
• Hexadecimal numbers are used to identify the location of memory on a memory map.
• MS-DOS can access only the first 1 MB of memory.
• Several commands, such as MEM.COM, are used to identify memory allocation in a computer.
• A computer technician must know the difference between conventional and high memory.