Unit 07: PC system
A. Read the text below and then sentences 1 to 8. Decide if the sentences are true (T) or false (F).
What's inside a PC system?
The nerve center of a PC is the central processing unit or CPU. This unit is built into a single microprocessor chip — an integrated circuit — which executes program instructions and supervises the computer's overall operation. The unit consists of three main parts:
i the control unit, which examines the instructions in the user's program, interprets each instruction and causes the circuits and the rest of the components — disk drives, monitor, etc — to be activated to execute the functions specified;
ii the arithmetic logic unit (ALU), which performs mathematical calculations (+, -, etc.) and logical operations (and, or, etc.);
iii the registers, which are high-speed units of memory used to store and control information. One of the registers is the program counter (PC) which keeps track of the next instruction to be performed in the main memory. Another is the instruction register (IR) which holds the instruction thatis currently being executed (see Fig. 1).
One area where microprocessors differ is in the amount of data — the number of bits — theycan work with at a time. There are 16, 32 and 64-bit processors. The computer's internal architecture is evolving so quickly that the new 64-bit processors are able to address 4 billion times more information than a 32-bit system.
The programs and data which pass through the central processor must be loaded into the main memory (also called the internal memory) in order to be processed. Thus, when the user runs an application, the microprocessor looks for it on secondary storage devices (disks) and transfers a copy of the application into the RAM area. RAM (Random Access Memory) is temporary, i.e. its information is lost when the computer is turned off. However, the ROM section (Read Only Memory) is permanent and contains instructions needed by the processor.
Most of today's computers have internal expansion slots that allow users to install adapters or expansion boards. Popular adapters include high-resolution graphics boards, memory expansion boards, and internal modems.
The power and performance of a computer is partly determined by the speed of its microprocessor. A clock provides pulses at fixed intervals to measure and synchronize circuits and units. The clock speed is measured in MHz (megahertz) or GHz (gigahertz) and refers to the frequency at which pulses are emitted. For example, a CPU running at 1,600 MHz (1 millions cycles per second) will enable the computer to handle the most demanding applications.
Central processing unit (CPU) | Organization of a simple computer | ||||||||||||||||||||||||||||||||
Control Unit | Main memory | ||||||||||||||||||||||||||||||||
Arithmetic Logic Unit |
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Registers
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A RAM chip
Microprocessor chip
Popular chips:
Intel's Pentium (as shown)
AMD's Athlon
Apple and IBM's Power PC
Sun's UltraSPARC
The RAM capacity can sometimes be expanded by adding extra chips. These are usually contained in small circuit boards called single in-line memory modules (SIMMs). Modern Pentium processors also accept dual in-line memory modules (DIMMs), DDR2, and DDR3 which allow for a wider data path.
01. The CPU directs and coordinates the activities taking place within the computer system.
02. The arithmetic logic unit performs calculations on the data.
03. 32-bit processors can handle more information than 64-bit processors.
04. A chip is an electronic device composed of silicon elements containing a set of integrated circuits.
05. RAM, ROM and secondary storage are the components of the main memory.
06. Information cannot be processed by the microprocessor if its not loaded into the main memory.
07. 'Permanent' storage of information is provided by RAM (random access
memory).
08. The speed of the microprocessor is measured in gigahertz or megahertz.
09. One GHz is equivalent to one thousand MHz.
10. One MHz is equivalent to one million cycles per second.
Contextual Reference
Recebem o nome de REFERENTES aquelas palavras cuja função é a de referir-se a outros elementos que podem já ter sido mencionados anteriormente no texto ou que ainda o serão. Os principais referentes são:
B. What do the words in bold print refer to?
1... which executes program instructions and supervises.. | |
2... the instruction that is currently being executed. | |
3... the amount of data — the number of bits — they can work with at a time. | |
4 ... the microprocessor looks for it on ... | |
5 ... its information is lost when the computer is turned off. | |
6 ... expansion slots that allow users to install adapters or expansion boards. |
Word Formation 02 : Acronyms
Dentre os métodos de formação de palavras, encontramos um que é bastante popular na área de Informática: o uso de acronismos (siglas). Por exemplo: ALGOL, BASIC, COBOL, FORTRAN, etc.
Extra Activity:
Acronym Finder
Database
//www.acronymfinder.com/
This is a Website about technical acronyms and abbreviations.
A. Enter the site and find the meaning for these Information Technology terms.
B. Do you like this acronym finder? If so, add the website address to your Favorites or Bookmarks folder.