Compatibility Guide

Glossary 173

HMA

Abbreviation for high memory area. The first 64 KB of extended memory above

1 MB. A memory manager that conforms to the XMS can make the HMA a direct

extension of conventional memory. Also see XMM.

host adapter

A host adapter implements communication between the system's bus and the

controller for a peripheral device. (hard drive controller subsystems include

integrated host adapter circuitry.) To add a SCSI expansion bus to your system,

you must install or connect the appropriate host adapter.

hot plug

The ability to remove and replace a redundant part while the system is still running.

Also called a "hot spare."

HPFS

Abbreviation for the High Performance File System option in the Windows NT

operating systems.

HTTP

Abbreviation for Hypertext Transfer Protocol. HTTP is the client-server TCP/IP

protocol used on the World Wide Web for the exchange of HTML documents.

HTTPS

Abbreviation for HyperText Transmission Protocol, Secure. HTTPS is a variant

of HTTP used by Web browsers for handling secure transactions. HTTPS is a

unique protocol that is simply SSL underneath HTTP. You need to use "https://"

for HTTP URLs with SSL, whereas you continue to use "http://" for HTTP URLs

without SSL.

Abbreviation for hertz.

ICES

Abbreviation for Interface-Causing Equipment Standard (in Canada).

ICMP

Abbreviation for Internet Control Message Protocol. ICMP is a TCP/IP protocol

used to send error and control messages.