BOOT CAMP 067

NETWORKING PCs PART 1

A network is basically two or more PCs communicating with one another. It could be something as simple as a laptop or palmtop swapping files with a desktop machine, a group of PCs in an office sharing common resources like files and directories or printers and modems, or the mother of all networks, the Internet. In an ideal world connecting computers together should be easy, as indeed it is if you own an Apple Mac, but the original IBM PC upon which all Windows machines are based, was designed as a stand-alone device.

Getting PCs to communicate with one another can be horribly complicated involving more technical gobbledegook and acronyms than you can shake a stick at. Thankfully Windows 95 and 98 has taken much of the sting out of getting hooked up to the Internet but simple one to one connections can still cause major headaches. This week we're going to take a brief look at how networks operate. In part two we're going to have a go at setting up Windows 95/98 built-in networking facilities for a PC to PC connection, known as the Direct Cable Connection or DCC to its friends (and many enemies…).

Computer networks take many different forms but the commonest type is the Local Area Network or LAN, where all of the computers are physically close to one another in the same room, office or building. LANs can be further sub-divided into two types. Larger networks use what is known as a 'Client/Server' system with a fast and powerful central computer -- called the server -- running a network operating system (NOS) program that controls and communicates with all of the client PCs. The second type of LAN, and the one most appropriate one for home and small office use, is the 'Peer to Peer' network, where all of the PCs have a common status and share and have access to each others resources (disc drives, printers etc.).

Networked computers communicate using a common language or 'Network Protocol', the two most widely used protocols are Ethernet -- mostly used on LAN systems -- and TCP/IP (transmission control protocol/Internet protocol) which is the language of the Internet. The Ethernet protocol works by sending data in small bursts or 'packets' along the cable connecting the PCs. Each PC in the network has to be fitted with a Network Interface Card or NIC that has a unique identity code or address, so it only receives data specifically meant for it. An Ethernet network can only handle one packet of data at a time but since data travels down the wires at the speed of light, and many millions of packets can be sent every second, it appears to operate more or less instantaneously.

The last consideration is how all of the computers are wired up, otherwise known as the network topology. There are three basic options, known as Bus, Ring or Star, most Ethernet LANs use bus or star topologies, so we'll look at those in more detail. In a bus system each PC in the network plugs into a wall socket or is jointed to a cable that runs around the office or building. In a star system each PC is individually connected to a device called a distribution hub. It's a bit like a telephone exchange that routes the data, administers the system and looks after all of the network's resources. Bus systems are easy to install but are more prone to cabling faults and errors that can bring down the whole network. Star networks are more complicated and require additional hardware but they are much more robust and tolerant of faults.

That's all very interesting but if all you want to do is exchange a few large files between your laptop and office PC, or use an old redundant PC as a backup machine it's unlikely you'll be interested in getting involved with serious network paraphernalia. Other than physically moving data from one PC to another on floppy discs or removable storage media (Zip, Jazz, CD-R/RW discs etc.), or sending files to your other PC over the Internet your home network options are dictated by the communications facilities on your PCs.

Broadly speaking there are two possibilities: you can connect the PCs together using serial/parallel cables or exchange data by cordless infra-red or wireless links. A growing number of laptops and palmtop PCs have infra-red data transfer facilities that operate without wires over a distance of a few metres. Unfortunately few desktop machines have it fitted as standard but it is possible to get hold of plug-in adaptors and communications software, (IR utilities are also included with the latest versions of Windows). Wireless links are also dependent on extra hardware to send and receive data via a pair of radio transmitters and receivers (transceivers) connected to both machines, however the technology is in its infancy and there are still a lot of problems to be resolved.

That leaves a direct cable connection between the two machines, which is far and away the best solution for most users since it is cheap and reliable. Nowadays virtually all handheld PCs and a few laptops come with docking stations or communications facilities for exchanging files with Windows desktop PCs. You can also buy specialist data exchange programs like LapLink, which work very well indeed but can be quite expensive. Alternatively you can use Windows DCC, the only problem with that is it can be difficult to set up. Data exchange on the PC involves many separate layers and operations so the two computers must be precisely configured. In short there are plenty of things that can go wrong but with patience it can be made to work and next week we'll show you how.

Next week -- grappling with DCC

JARGON FILTER

CORDLESS LINK

PC communication systems that do not involve the use of wires, i.e. data is sent by infra-red light or radio signals

NIC

Network Interface Card, a plug in card that fits into one of the PCs motherboard expansion sockets. NICs are also available in the form of PC cards, for use in laptops

NOS

Network Operating Software, a program running on a network server computer, the best known NOS programs are Novell Netware, OS/2 Warp Server, Open Server and Windows NT Server

TOP TIP

Here is a nifty little trick to access the contents of your desktop from the Start button, without having to close or minimise any windows. Right click on the Start button and choose Open then on the Start Menu window that appears go to the File menu, select New and Shortcut. The Create Shortcut window opens and in the Command Line box type in the following: 'Explorer /root,' ignore the inverted commas but sure there's a space between Explorer and the forward-slash, and don't forget the comma after root. Click Next and a window opens asking you to 'Select a title for the program'. Back space to delete the default entry and call it 'Desktop' (or anything else you fancy) and click Finish. The item should now appear on the Start menu, if you click it a window containing the contents of your desktop will open. To remove it from the Start menu go Start > Settings > Taskbar & Start Menu > Start Menu Programs tab and click the Remove button. Find the shortcut on the directory and click Remove.