2.1.4 Data Measurement

2.1.4.1 State the units of data measurements

Why is 1024 bytes = 1KB?

2kuasa0 = 1

2Kuasa1 = 2

2 Kuasa2 = 4

2Kuasa3 = 8

2Kuasa4 = 16

2Kuasa5 = 32

2Kuasa6 = 64

2Kuasa7 = 128

2Kuasa8 = 256

2Kuasa9 = 512

2Kuasa10 = 1024

KILOBYTE (KB)

In mathematics, 1 KB = 1000 bytes.

In computer, 1 KB = 1024 bytes or

can be said as:

1 KB = 210 bytes

This is how we get the calculation for 1024 bytes.

MEGABYTE (MB)

1 MB = 1 048 576 bytes or it can be said as:

1 MB = 220 bytes

GIGABYTE (GB)

1 GB = 1 073 741 824 bytes or it can be said as:

1 GB = 230 bytes

TERABYTE (TB)

1 TB = 1 099 511 627 776 bytes or it can be said as:

1 TB = 240 bytes

2.1.5CLOCK SPEED MEASUREMENT

EVOLUTION OF COMMUNICATION

When people talk about a computer’s “speed”, they mean how fast it can process data. In other words, this means the speed the computer can turn data into information.

Every microprocessor contains a system clock. The system clock controls the speed of all the operations within a computer. The speed of the clock is measured by how many cycles per second the clock makes.

HERTZ AND SECONDS

The clock speed unit is measured in hertz. A hertz is one cycle per second.

MEGAHERTZ (MHz)

Mega is a prefix that stands for million. Thus, megahertz (MHz) equals to one million cycles of the system clock. A computer that operates at 933 MHz (megahertz) has 933 million clock cycles in one second.

GIGAHERTZ (GHz)

Giga is a prefix that stands for billion.Gigahertz (GHz) equals to one billion cycles of the system clock.In relation with megahertz,1.0 GHz is equivalent to 1000 MHz.

For example, a microprocessor that runs at 200 GHz executes 200 billion cycles per second. This is what they are talking about if they say a computer is a 2.4 GHz machine. Its clock rate is 2.4 billion cycles per second.

GHz is most often used as a measurement of a PC processor chip and power, with bigger numbers meaning more speed and higher price.

PROCESSING SPEED

The system clock is one of the major factors that influence the computer speed. A CPU with a higher clock speed can process more instructions per second than a CPU with a lower clock speed. For example, a 1 GHz CPU is faster than a CPU operating at 800 MHz. The speed of the system clock affects only the CPU. It has no effect on peripherals such as a printer or disk drive.

MICROPROCESSOR SPEED

One way of comparing the performance of personal computers is by comparing their microprocessor speeds. Microprocessor speeds are determined by their clock speed and are usually expressed in gigahertz (GHz), billion of machine cycles per second.

For example, a personal computer that is listed at 2.2 GHz has a processor capable of handling 2.2 billion machine cycles per second. A top speed personal computer can be much faster, with newer ones exceeding 3.0 GHz.

Direct comparison of clock is meaningful between identical microprocessor.

Thus, it is accurate to say that a Pentium 4 running at 2.4 GHz is approximately one-third faster than a Pentium 4 running at 1.8 GHz.

SPEED AND PATH

The combination of speed and number of paths determines the total processing speed or channel bandwidth. This is because different processors

often use different architectures. For this reason, a 1.4 GHz Pentium 4 performs better than a 1.4 GHz Pentium 3, but it is not as fast as a 1.4 GHz Power PC G4 processor.