How to select an old computer?
This document was prepared in Jan1995 to advice people on buying new computers. It is very interesting to look back because it is almost history. It may be useful for people looking for an used computer.
New products keep on emerging, therefore, prices keep on going down by the day
because of obsolescence. Distributors purchased pre-assembled products from the
factory, and by the time they could display their merchandise is no longer
current on price and performance. To keep ahead of time, and price economy,
custom order a computer is a wise choice.
Do not buy the best computer for business and give your old computer to the kids
to play. You should do the reverse way, because graphics and games require a
much faster high performance computer than a business computer.
Most current CPUs are Pentium 100, 90, 75, 66, and 60. 486s will be phased out
in the near future. You need minimum of 4 M byte of memory to run Windows
programs. 16 M byte with parity check is more preferable. Hard disk prices are
keep on falling, 540K is already standard, 730K is deluxe. 1G will be standard
in the near future. Double speed CD-ROM is current, but it will be replaced by
quad speed in the very near future.
On buying a slow computer with minimum memory, and with a small hard disk. It
may cause trouble in your future upgrade. A slow computer may not be able to
handle your job in the future. It may turn out not worth to spend any more money
with it. If you expect to upgrade your memory in the future, make sure you get
the minimum number of strip of memory modules with the maximum amount of memory.
Otherwise, you may have to discard some of your old memory because of no room to
install new modules. You may also have no room to install extra hard disk if
your case is too small.
Do not compare prices base on the data supplied by your dealer. These data are
usually looks attractive and are full of redundancy. You have to look more
deeply into the specifications. Such as the speed and manufacturer of the CPU
The mother board and bus system, cache memory, ram speed, parity checks,
hard disk size, access time, monitor resolutions, fax modem data speed, CD-ROM
speed, sound card bits, speaker poWer amplifier ratings, etc. Two computers with
identical list of components could have big different in cost price because of
supplier could replace them with some inferior components.
Name brand computers do not necessary mean better quality. In fact, they are not
necessary manufactured by themselves. Their products are usually OEM (Original
Equipment Manufacturer.) That is, they order the product from some cheaper
manufacturer to manufacture under their brandname.
If you have the need to buy a computer, then buy it without regret. In very
short time, you will find you are paying too much for it. If you want to wait
for the price drop, then, you will find your waiting is for ever. When you found
the price is right, you will also found it is no longer the thing people
Hi-Tech could help you to select the best and affordable computer. We are very
glad to explain to you at no charge. For your price and performance benefits, We
do not stock any item. Everything is custom for you. Please make appointment
with us if you have decided to buy.
486 and 586 are two main types of Central Processing Unit available
nowadays. They can have built in co-processor or without co-processor.
Co-processor is an additional special computer that performs mathematics. All
graphics and mouse movement will require mathematics to be performed, therefore
you will need co-processor even if you do not calculate. CPU can operate at
different speed. The communication bus could also operate at loWer speed than
the CPU. For example. A model 486SX2-50 is a CPU without co-processor, operating
at 50 M Hz with a loWer bus speed.
Pentium 100 is a CPU of 100 M Hz with built in co-processor operating at loWer
bus speed. For Pentium you are recommended to get 75 or 100 becuse 75 is at
loWer price and can be upgradable while 60, 66 can not.
PCI, VLB, ISA are three main type of bus systems. PCI and VLB are 32 bit
high speed bus systems. ISA are classic 16 bit system. Most motherboard will
include ISA because there are still some slow speed devices such as modem will
require them. On selecting a mother board, you can specify the chip
CPU does not communicate directly with memory because of different level
of speed. Therefore, they require some high speed memory as scatchpad. With
todays standard, 128K is minimum, 256K is average, 512K and 1 M are options.
You do not need much memory if you run only DOS programs. Most DOS
programs can access up to 640K memories only. If they run higher than 640K, they
will require special system configurations to operate the expanded or extended
memories. Otherwise, you may still have running out of memories even you
actually have plenty of available memories. Windows programs require lot of
memories. 4 M Byte is minimum, 8, 16 are recommended.
Memories constitutes nearly 1/3 cost of the whole computer. Motherboard
can accommodate certain number of strips of memories. Memory strip manufactured
in different memory configurations. Therefore, if you purchase a computer, make
sure they are easily upgradable. Otherwise, you may have to discard some or even
all of you old strips. Lot of brandname computers do not use standard
configurations, therefore, you will expect to pay much more money.
Parity check is a feature to cross checking the error during program
execution. Memory with parity check feature has 9 bit instead of 8 bit. Low end
product do not have parity check.
200M hard disks are considered small in nowadays standard. 540M is
recommended. 1 G will take over soon. IDE and SCSI are two common interfaces.
They are equally good and reliable. IDE is more common. SCSI is faster. Modern
hard disk access times are usually 10-20 m sec. Hard disk controllers can have
8, 16, or 32 bit configurations. 16 bit access are normally used even if you
have a 32 bit bus, unless you have configurated it with 32 bit data access.
Therefore, you must specify your supplier to configure them or you are wasting
money to purchase such an advanced system.
One 1.44 M floppy will be enough.
Keyboard, mouse 101 Enhanced keyboard
are standard. Mouse are also very reliable in nowadays. People are more
concerned on fashions and cosmatics.
Super VGA, interlaced, non-interlaced, refresh rate are not too important
to be considered. A very low priced monitor can still have very high performance
in nowadays technology. Do not waste money on feature selections, they may
turned ou to be the same product. You must get a high resolution CRT for good
view. A 0.28 CRT is considered
good, 0.31 is fair, 0.39 is poor.
VGA control card can cause lots of program conflict if it is not properly
selected, matched, and configured. Improper selection can have screeen
interference, program hang up, lost of hard disk cluster etc.
CD-Rom is a very slow device. They are still under improvement. Quad
speed will replace double speed soon.
You must specify 16 bit when you purchase them. Low end product could
substitute with 8 bit product.
You can get speaker only, speaker with booster, speaker with poWer
amplifier, or just a cable to hook up to you stereo system.
Fax modem speed are keep on increasing. It is not necessary for you to
operate at maximum speed just because you have a fast modem because you speed is
actually determined by you line quality, and your host.
Nowadays, modem can be operated as terminal, internet, Fax machine, Fax on
demand, voice mail, ansWering machine, and etc. at surprisingly low price.
Network is useful to share resources betWeen computers. It is very useful
if you have two or more computers. Accounting programs must operate in a network
environment if you have two or more terminal. With the advance of technology,
networking is no longer limited to large coporations. For as low as $200. You
can set up a very high performace network.
High speed CPU requies extra cooling to extend its life and to reduce
You can select desk top model for good looking or toWer model for space
saving. Mini size with two expansion slot is already adquate for most purpose.
Mid toWer size will alow more room for future expansion. Full size is too big
for home use.
Green feature Green feature is a energy
saving system which can loWer your CPU speed, standby, suspend you computer ,
monitor, hard disk , etc on idling. Green feature could cause conflict on
certain program. It may not work as desired.
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