Cmos Memory

Configuration settings of a computer such as storage capacity, memory capacity (RAM), and display configurations also need to be stored permanently. This information is stored in CMOS (complementary metal oxide semiconductor) memory. The CMOS chip requires very little electrical power to hold data. It can be powered by a small battery on the motherboard, or packaged with the chip. The battery maintains the data on the CMOS when the computer is turned off.

More about the role of BIOS and CMOS in booting a computer will be discussed later in unit 4: Operating System Software.

Summary

The decision diagram below indicates under what circumstances each memory device is needed.

Figure 3 Memory decision tree

The chart below shows the different memory devices including the register, which stores the results of CPU operations. The chart also lists the relative price, memory capacity, latency, and location of each device.

Memory	Cost	Capacity	Latency	Location
Register	$$$$	8-128 bits	almost instantaneous	On CPU close to the ALU
L1 Cache	$$$	1-100 KB	~1 ns	On the CPU
L2 Cache	$$	100-1000 KB	~1 ns	Between the L1 cache and the RAM
DRAM	$	1-1000 MB	~10 ns	Outside the CPU on the motherboard

Table 2 Comparing memory devices

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2.1.3 Lab: Benchmarking (Optional)

Benchmarking, which is the process of running standardized tests upon differing configurations to determine the speed of components or software was briefly mentioned in 2.1.1 Processor Basics. This lab will give you a greater understanding of benchmarks by having you download Fresh Diagnose, an application that allows you to analyze and benchmark your computer system. You will use the software to compare the benchmarking results of your processor with those of your classmates.

Note: This lab is to be performed on Intel-based computers running Windows 95/98/NT4/2000/XP/ME.

Learning Exercise: Download Fresh Diagnose and install it. (1102 kb download) Run the application. Click on Benchmarks on the left-hand side menu. Pick Processor Benchmark and click on Start on the upper-right corner of the application screen. Compare your results with those of your classmates. Try another benchmark and compare your results with those of your classmates. You can also explore your system's properties through the other options on the left-hand side menu.

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2.2 Peripherals

In addition to the microprocessor and the memory, a computer also has other devices such as the monitor, printer, keyboard, and speakers. These peripheral devices are connected via ports to the computer. Buses inside the system unit transport data among components in a computer and connect all peripheral devices to the CPU and memory. In this section, you will learn about the various types of ports and buses. You will also become familiar with some important peripheral devices of a computer.

Reading Sequence: 2.2.1 Connecting Peripherals. Learning Goal: Knowledge of how components such as expansion slots, expansion cards, and types of connectors and ports used to transfer data between peripherals and the computer system. Parsons/Oja, Chapter 2-Section D . Learning Goal: More in-depth knowledge of expansion slots, cards, and ports in a computer system. 2.2.2 Buses. Learning Goal: Familiarity with types of bus standards used to transfer data within a computer. 2.2.3 Input/Output Devices. Learning Goal: Knowledge of various types of input and output devices. Some input devices discussed are digital cameras and webcams. Some output devices discussed are monitors and printers. Parsons/Oja, Subsections "Installing Peripheral Devices," "Display Devices," and "Printers" in Section 2D. Learning Goal: Knowledge of the different types of printers and monitors available. Parsons/Oja, Chapter 8-Sections A-D. Learning Goal: Knowledge of how visual and audio digital equipments work.

 

Assessments: Multiple-Choice Quiz 5

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