1. The document introduces the basic components and functions of a computer, including how information is received as input, processed by the CPU and memory, and produced as output. 2. It describes how information is stored and represented digitally using bits, bytes, and binary and ASCII encoding systems. 3. The core components of a computer are explained as the CPU, which executes instructions stored in memory, and memory itself, which temporarily stores data and program instructions. Other components like buses, ports and peripherals are also outlined.

1. Hardware Basics:
Inside the Box
Miguel Rebollo
Introduction to Computer Science
2009-2010

2. Aims
• Know how information is stored and
handled into a computer
• Describe the basic structure of a computer
• Functions and interactions of computer’s
internal components
• Difference memory types and storage
devices
4626. Introd to Computer Science

3. Outline
1. What computers do
2. A bit about bits
3. The computer core: CPU and memory
4. Buses, ports and peripherals
4626. Introd to Computer Science

4. What computers do
• Receive input data
• Process this information: perform
arithmetic or logic (decision-making)
operations
• Produce output: communicate information
to the outside world
• Store information: move data to the
memory
4626. Introd to Computer Science

5. Basic components
Storage
Input devices: Output devices:
keyboard screen, printer,
and mouse speakers
CPU
Memory
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6. Von Newman archit.
CPU
system i/o bus
input/output
bus(*)
memory
(*) front side bus
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7. A bit about bits
• computer’s information is digital
• Bits can represent letters, numbers,
instructions, codes, colours and so on
• 8 bits = 1 byte (256 different values)
4626. Introd to Computer Science

8. Bits as numbers
There are only
10 types of people in the world:
those who understand binary
and those who don’t
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9. Binary number system
decimal binary
• All numbers as 0 000
combinations of two
digits: 0 and 1 (base 2) 1 001
2 010
• conversion 3 011
binary-decimal 4 100
5 101
• with n digits we have 2n
6 110
possibilities
7 111
Play with the numbers
4626. Introd to Computer Science

10. Bits as characters
• Each character has its representation in bits
• ASCII (see table)
• the most widely spread
• fixed codification (1 character = 1 byte)
• Unicode (UTF)
• until 65,000 char., language independent
• variable codification (1 or 2 bytes)
4626. Introd to Computer Science

11. ASCII code
• ASCII code uses 8 bits
• 8 bits produce 2 =256 possibilities
8
• It’s not enough, several codes added
• mutually incompatible
• changes in special letters (ñ, á, ç, ...)
4626. Introd to Computer Science

12. Bits, bytes and
buzzwords
• Bit-related terminology
1 Byte =
1 kilobyte (kB) = 1024 Bytes
1 megabyte (mB) = 1024 kB
1 gigabyte (gB) = 1024 mB
1 terabyte (tB) = 1024 gB
1 petabyte (pB) = 1024 tB
1 exabyte (eB) = 1024 pB
• Other units: Zettabyte,Yottabyte...
• See Data Powers of Ten
4626. Introd to Computer Science

13. The computer’s core:
CPU
• It’s the main component of the computer
• Executes program’s instructions
• Instructions are stored in memory
• Input data and results are stored in
memory too
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14. Evolution of Intel proc.
Intel processor history
4626. Introd to Computer Science

15. CPU equivalence
Intel AMD
Obsolete Pentium 4 Athlon 64
Low-end Celeron Sempron
Core 2 Duo, i3, i5 Athlon 64 x2
Desktop
Core 2 Quad, i5, i7 Phenom
Laptop Centrino, i3, i5 Turion
Netbook Atom -----
Servers/ Xeon Opteron
Workstation Itanium -----
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16. CPU performance
• The computer’s overall performance is
determined by (among others)
• the internal clock (gHz): cycles per
second
• the internal architecture
• Two technologies: CISC and RISC
• Multiple core and Hyperthreading tech.
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17. CPU compatibility
• Each CPU has its own instruction set
depending on the manufacturer (Intel,
Alpha...)
• CPUs in the same family are designed to
maintain backwards compatibility (new
models interprets all instructions from
earlier CPU)
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18. RAM memory
Stores temporally
program instructions and data
• it’s volatile
• divided in smaller
elements (bytes)
identified by its
address and
managed individually
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19. ROM
(read only
memory)
information stored in
chips
contains startup
instructions
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20. Other memories
• CMOS
(Complementary Metal
Oxide
Semiconductor): Special
low-energy kind of
RAM
• Flash memory: used in
phones, PDA or
cameras
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21. Buses, ports and
peripherals
• Information travels between components
on the motherboard through groups of
wires called system buses (or just
buses)
• They have 32 or 64 parallel wires
• Expansion slots, bays and ports: connect
additional devices
4626. Introd to Computer Science