deutsche VersionA preliminary note: information about computers is short-lived, because the development of new components progresses rapidly. To stay up-to-date, it is necessary to follow a good computer magazine. If you read German, I very much recommend c't magazine, because it is filled with in-depth technical information, independent hardware and software tests and critical articles. You definitely don't buy it for the adverts, although it contains lots of them also. Look for a 500 page book at the newsstand. In my opinion, this is by far the best German computer magazine, and probably the world's most serious and technical computer magazine.
I present here an updated translation of a text I have originally written for my prospective customers, in order to save me from saying the same things over and over again. Because I am dealing with PCs (i.e. intel-based computers, formerly known as IBM compatibles when IBM was still setting standards in this market), this is the only computer type discussed here; clearly other computers have their applications too and may be a better option depending on the circumstances. But no other computer type has as large an diverse a market and hence does not require as much guidance either.
It is quite normal, and sensible, to upgrade and modify a computer during its life. Therefore one should consider when buying, which components are more permanent and which ones are likely to be exchanged. For the short-lived components, inexpensive options should be considered as the second-hand price tends to be fairly low, and very advanced parts (like the newest, fastest CPU) tend to experience the largest drop in price over the next year or two, while older components' prices tend to stabilize.
(piccy with outdated German prices omitted)
Certain upgrades do not involve the replacement of parts: e.g. you can add another harddisk or more RAM without removing what you've got already. Other parts -- like the motherboard, graphics adapter, monitor -- can only be replaced. For them it is sensible to anticipate future needs.
Some components are not really necessary for a computer to work, and can be added later when needed at no or little additional cost (or even saving money because component prices tend to drop steadily). This is true for external devices like scanners, printers, modems, but also for some internal components like sound cards, tape streamers, removable disk drives, SCSI adapters (when starting with an EIDE system).
Today, the usual shapes are minitower and big tower, both are standing-up cases which contain the motherboard mounted vertical along the lower right-hand side (seen from front).
The minitower usually has two 5.25" and two 3.5" open drive bays, plus some more 3.5" hidden bays usable for harddisks. Big towers have 5 or 6 5.25" drive bays and usually 2 open and 3 hidden 3.5" drive bays.
Large (5.25") drive bays are needed for:
A small (3.5") bay is sufficient for:
Small devices can always be places in a large drive bay using a mounting frame.
Apart from the number of drive bays, there is one significant difference between minitowers and bigtowers: Although minitowers also support 6 to 8 slots of a motherboard, they have a much smaller lower body, so the disk drive bays may interfere with long adapter cards. Minitowers are not very maintenance-friendly because things are so tightly packed. Not all motherboards will fit into a minitower, so you are reducing the choice of motherboards somewhat by choosing one.
There is an in-between size called midi-tower, but this is not well-defined: some people call this a slightly higher mini tower, which just has one more large drive bay, while others refer to a cut-off big tower by this name. The latter, also called middle-tower sometimes, is quite a sensible option.
Do not buy a CPU that has an external clock rate other than 66MHz: the 75MHz needed by the Cyrix/IBM P200+ result in a non-standard clock rate on the PCI bus, and 50 or 60MHz wastes precious PCI bandwidth, slowing the system altogether (with typical PC chipsets, the PCI bus runs at half the external CPU clock, i.e. 25, 30 or 33 MHz for 50, 60 or 66MHz external CPU clock. The chipset, second-level cache and RAM access run at the full external clock speed). This means: get an intel P100, P133 or P166, or an AMD PR100, PR133 or PR166, or a Cyrix/IBM P166+ if you must. I don't recommend the Cyrix/IBM because of their poor 32bit and float performance.
Under no circumstances should you buy too little RAM. I refuse to sell less than 32MB except for a very low-end PC, and recommend 64MB for power-users. It is better to buy a slower CPU and more RAM, because swapping kills system performance by one or two orders of magnitude, and CPU speeds do not significantly differ compared to that!
You should get 60ns EDO RAMs for best performance. Parity is not worth the money for a workstation machine in my opinion, as it is significantly more expensive.
SCSI is the more stable, more versatile and extendible system: a bus can be shared between 7 devices in addition to the host adapter (equivalent of controller). Several devices can use the bus interleaving, allowing good throughput even during concurrent access. In addition to harddisks and CD-ROM drives, SCSI supports all sorts of devices, like scanners, MO drives, CD writers, removable disks, various streamers (QIC, Exabyte, DAT). There are standards for external connectors and SCSI cables.
I recommend SCSI to the advanced PC user, and EIDE to others. Systems with EIDE components can later be upgraded by adding a SCSI adapter and SCSI divices, which will co-exist with EIDE devices without any problems. With older BIOSes, one cannot boot from a SCSI disk when an EIDE disk is present, but Adaptec controllers or NCRs with a new motherboard BIOS can override this.
Because of significant difference in price, I think one can use a EIDE/ATAPI CD-ROM drive even in an otherwise SCSI system. One exception is when direct copy to a CD writer is required; this is only recommended from a SCSI CD reader because of the high demand on the timing of the read operations.
The size of harddisk is always a topic for discussion. I think that at present something between 1.6 and 2.5GB is a good start for a desktop machine. For SCSI, IBM harddisks are very good indeed, although often hard to obtain. For power-SCSI systems, the IBM DCAS 4GB is the harddisk of choice, offering very good value of money (a 5400 rpm disk with the specs of a 7200rpm disk: silent, likely to last very long, while still very fast!).
If you have enough space (depth about 55 to 60cm -- 22 to 24in), you should really spend your money on a 17" monitor (82kHz horizontal frequency minimum; 64kHz is inadequate for high resolutions). This allows a comfortable 1024×768, and will support 1280×1024 if need be. Otherwise a 15" monitor will have to do, typically with 800×600.
I have found that the CTX monitors offer good value for money, but I may be a bit biased because I have a distributor for CTX monitors very nearby.
(c) 1996 Karl Ewald, Hardware Software Beratung. This is an information sheet for my customers. Reprint and redistribution requires my permission.