UNIVERSITY OF COLOMBO

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UNIVERSITY OF COLOMBO SCHOOL OF
COMPUTING
IT1301 Fundamentals of Computer Systems PC
Applications
DEGREE OF BACHELOR OF INFORMATION TECHNOLOGY
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Q 1 The binary pattern 101110 is an answer
received after adding two numbers in a 6-bit
twos complement system. The answer in decimal
system is,   (a) 45 (b) - 44   (c) 18 (d)
13 (e) 45
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1 01110

• 101110
• 1
• 101101

010010
Invert
Convert to decimal
18
4
The binary number 1011000101111 can be equivalent
to (a) 54271 (b) 5679 (c) 13057 (d)
B171 (e) 162F
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1011000101111
F
2
6
1
1011000101111
1 3 0 5 7
1 2 4 8 32 512 1024 4096 5679
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•  The advantage(s) of using a hierarchical storage
  system in the computer organization is/are
•  (a)    It reduces the overall cost of a
  computer.
• (b)   It enables the use of favorable
  characteristics of different storage
  technologies.
• (c)    It has directly contributed to the fast
  growth of the Internet.
• (d)   It has enabled the sharing of information
  even in a non-networking environment
• (e)    It has increased public awareness of
  computing.

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Characteristics of Computer Storage Facilities

• Location

Inside the CPU
Cache memory
Main Memory/RAM/Internal Memory
External Memory / Backup Storage

• Physical nature

Volatile / Nonvolatile
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Characteristics of Computer Storage Facilities

• Type

Electronic Semiconductor
Magnetic
Optical

• Capacity

Fixed / Removable

• Speed

Access Method Random, Direct , Sequential
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Memory Hierarchy
CPU registers Cache RAM Secondary Storage
Capacity
Speed
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In the following table, A and B are the inputs
and X is the output.

• This Table can represent
• Odd parity (b) Even Parity
• (c) 1s complement addition (d) Single bit
  binary addition
• (e) Exclusive OR

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The minimum complete requirements to have the
Internet facility for a home user are  (a) Modem,
PC, Browser, Firewall, Telephone Connection.  (b)
Telephone connection, PC, Network card, Service
from an ISP.  (c) Modem, Telephone connection,
Service from an ISP, PC, Browser.  (d) Service
from an ISP, PC, Router, Network Interface.  (e)
Browser, Modem, PC, Telephone link, Firewall,
Router.
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Which of the following statement(s) is/are
correct in explaining the hard disk
technology?  (a) The capacity of a cylinder is
the same as that of a track.  (b) The boot record
is in the first sector.  (c) A sector can contain
a few cylinders.  (d) Each surface should be
accessed with at least one head.  (e) All the
heads move in and out together.
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Storing Data
Data is stored on the surfaces of a platter in
sectors and tracks. A sector contains a fixed
number of bytes for example 256 or 512. Either at
the drive or the operating system level, sectors
are often grouped together into clusters.
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Hard Disks
When powered up, the platters are constantly
rotating (except for certain pre-programmed sleep
modes) and the heads are moved back and forth
across the surface to access different locations.
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Read/Write Heads
Since both sides of each platter are used, there
is one electromagnetic read/write
head for each side of each platter.  
Each head is mounted onto the end of an access
arm and these arms are moved together under the
control of a single actuator mechanism.
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Contact
External Degree Unit (EDU) of the Institute of
Computer Technology No. 221/2A, Dharmapala
Mawatha, Colombo 7. Phone [phone] Fax
074-720512 Email bit_at_ict.cmb.ac.lk htt
p//www.ict.cmb.ac.lk/bit.htm