The very first IBM PC, like the one that holds down the floor in the back closet
of my office, was introduced with a base memory of 16K. That’s 16 kilobytes;
a kilobyteis roughly^1 ⁄1,000of a megabyte depending how you do the counting. A
modern laptop with 256MB of RAM has about 16,384 times as much memory.
Handling memory .................................................................................
How much memory can your laptop handle? In two words... it depends.
Older machines may have been built around motherboards and chipsets that
can work with only 256MB, while modern machines use designs every bit as
capable as a desktop PC, with capacities for 1GB or more of RAM.
When all else fails you should read the instruction manual that came with
your machine. You can also give the manufacturer a call; be prepared with
the model name, model number, and serial number.
You also find some valuable online tools at the Web site of your manufacturer
and at the sites of several third-party memory sellers. You can research the
capacity and type of memory used in your machine at model sites such as
http://www.dell.com and http://www.gateway.com. Belarc Advisor is a free utility that
explores your machine and produces a full report on installed software and
hardware. The company promises that information is maintained on your
machine and not transmitted to persons unknown. You can find it at
http://www.belarc.com/free_download.html.
You also find that many laptop makers include a diagnostic program on your
machine. A report examining the configuration may be included. For exam-
ple, Figure 6-1 shows a report generated by the Toshiba PC Diagnostic Tool
on one of my machines.
I also visited a database of information at the Crucial memory site to learn
about an older machine in my office, a Gateway Solo 2500SE. I was advised that
the maximum capacity for the Gateway 2500SE is 288MB. I also learned that the
machine had two memory slots, organized as two banks of one. That’s a nice
simple statement, right? Right.
Here’s what that means: In addition to any memory permanently installed on
the motherboard, two slots allow for expansion, and they are (in this machine)
electrically separated into individual banks. This allows me to add one or two
expansion modules; I can install both at the same time, or one at a time, and
they can be of the same capacity or different from one another. (As I already
discussed, though, they must be of the same physical design to fit in the avail-
able slots, and use the same memory technology, although they can differ in
refresh speeds and how often the system writes and rewrites data to individual
memory locations.)
Chapter 6: Brain Matters: Memory, Microprocessors, and BIOS 81