Specifications

9
In our familiar decimal system, each column of digits goes up by a factor of 10. The number 3723
is represented by 3,723 with a comma often separating each of the sections worth a thousand. In
the binary system that computers understand, 3723 is represented by the number 111010001011
for which each column represents a factor of 2. Each column is twice the value of the column to its
right. We count by 10’s (fingers). Computers count by 2’s (on/off transistors).
The binary digits that computers use are called “bits.” These bits are organized into “words”
containing eight bits called, in a fit of early computer geek humor, “bytes.” It is these words that
commonly describe capacities such as a kilobyte, megabyte, gigabyte, and so forth. Because
these capacities are based on a binary system, there is often confusion about the true value of the
numbers. A kilobyte literally means “1,000 bytes”; but because the number base is a 2, not a 10,
the closest binary number to 1,000 is 2
10
or 1,024. A kilobyte is actually 1,024 bytes in the binary
way of counting. The base 2 math appears in the order of capacities of flash media: 4MB, 8MB,
16MB, 32MB, 64, 128MB, 256MB, 512MB, each being double the previous version.
0
200
400
600
800
1000
1200
2HD floppy
disc
flash card
16 MB
flash card
32 MB
flash card
64 MB
flash card
128 MB
flash card
256 MB
flash card
512 MB
flash card
1GB
CD-R
Flash Media Capacities
unformatted capacity in MB
STORAGE MEDIA
In the earliest days of computers kilobytes meant a lot of information. That did not last long.
Technological progress has made computers faster, smaller, and less expensive and has made
the storage media for them capable of greater capacity while also shrinking their size and cost.
Memorex’s half-inch computer tapes gave way to 8” floppy disks, then 5 ¼” diskettes, then the 3.5”
diskettes that are now being replaced by CD-Rs and CD-RWs. The ideal memory storage product
has been a medium that offered a number of advantages that no previous media had offered
before:
• small, light-weight, portable format
• high storage capacity (Figure 1)
• fast data transfer
• erasable
• no moving parts to be misaligned or calibrated
Figure 1