| Word or
Term |
Description
or Explanation |
| Half Duplex |
an asynchronous communications protocol in
which the communications channel can handle only one signal at a time - the
communicating stations alternate between transmission and reception |
| Handshake (1) |
two modems trying to connect, first do this
to agree on how to transfer data |
| Handshake (2) |
a series of signals sent back and forth
between sending modem and receiving modem to ensure that data is not lost
through overflow, i.e. if the data is arriving faster than the computer is
storing it |
| Handshake (3) |
at a computer level, it is the process of
agreeing about a protocol and also the process of exchanging protocol
information |
| Hard drive |
a case containing a number of rigid metal
discs covered with magnetised material that can be used to store data - it
usually has a capacity of several megabytes or even gigabytes |
| HD |
hard drive |
| HDTV |
High Definition TeleVision, not to be
confused with widescreen TV - HDTV is television transmitted at double the
resolution of current services - this requires a special television set capable
of receiving the beefed up signal - HDTV takes up more bandwidth space than
lower resolution transmissions, so most broadcasters have opted to transmit
more channels within their allocated transmission space rather than go with
HDTV |
| Header |
the top of an email or Usenet message
containing the details of the sender, date, time, routing and other technical
information - much of the header is of limited interest to the average user,
and is therefore sometimes filtered out by an email or newsreader package |
| Hierarchical |
this is usually used in referring to the data
structure on storage media - see Directory |
High density
floppy discs |
discs that can store approximately 1,600Kb of
data when formatted under ADFS or up to 1,440Kb when formatted under MSDOS |
| High level language |
this refers to a computer language in which
instructions that the programmer enters are each converted into a number of
machine code instructions by a compiler or an interpreter - Basic, Fortran, C
etc are high level languages, whereas assembly language is a low level
language |
| Holy war |
arguments that involve certain basic tenets
of faith, about which one cannot disagree without setting one of these off -
for example: IBM PCs are inherently superior to Macintoshes |
| Host |
from a user's point of view, a host is a
computer or service which allows you access to the Internet. - more
technically, it is a computer running a protocol stack which is connected to a
network - each host has a numeric address which is unique to the network, and
usually a host name as well - in this context, the protocol stack will probably
be the Internet Protocol Suite, the network will be the Internet and the
numeric address will be an IP address |
| Host Name |
the name given to an individual computer,
e.g. the machine that handles mail at Demon is called "post", and combining
this with its domain gives its full Internet address of post.demon.co.uk - you
can invent your own hostname when joining Demon |
| Hourglass |
this is the egg-timer thing that appears on
the screen all too often, telling you that the application is taking a long
time to do something and that it doesn't want interrupting |
| HSV |
Hue Saturation Value - this is a
colour-picking system for use in DTP |
| HTML |
Hyper Text Markup Language - language for
creating Web pages |
| HTTP |
HA variant of HTTP for handling secure
(encrypted) data exchange on the Web by means of the SSL protocolyper Text
Transport Protocol - for fetching linked Web pages |
| HTTPS |
a variant of HTTP for handling secure
(encrypted) data exchange on the Web by means of the SSL protocol |
| Hub |
a device to connect computers on the same
network/segment of a network together - every piece of information transmitted
is sent to all the other computers/devices connected to the hub - typically
they run at 10Mbs |
| Hypertext |
a system enabling a reader to move between
related pieces of information by clicking on linking keywords or pictures |