WAEC SSCE - Computer Studies - 2014 (Essay)

(a) Three criteria used in classifying files

1. Nature / purpose of the file (for example master file, transaction file, reference file, backup file).
2. Organisation or method of access (serial, sequential, indexed-sequential or random/direct access).
3. Type of content or storage medium (for example text, program, data or graphic files; or the medium such as disk or tape file).

(b)(i) Advantages and disadvantages of computer files

Two advantages:

1. Large volumes of data can be stored in a small space and retrieved quickly.
2. Files can be easily updated, sorted, copied and shared, and they reduce paperwork.

Two disadvantages:

1. Files can be lost or corrupted through virus attack, disk failure or power problems.
2. Data in files can be accessed or altered by unauthorised persons if not properly secured, and recovery may be costly.

(b)(ii) Three methods of file security

1. Use of passwords and access rights so that only authorised users can open or edit the file.
2. Encryption of the file so that its contents cannot be read without the key.
3. Regular backup of files (and use of anti-virus software / write-protection) so that data can be restored if the original is lost.

(a)(i) Three application areas of a word-processing program:

• Typing and formatting letters, memos and business correspondence (including mail-merge for many recipients).
• Producing reports, projects, books and manuals.
• Preparing forms, resumes/CVs, notices and certificates.

(a)(ii) Three types of data item:

• Numeric data (numbers, e.g. 38, 71)
• Alphabetic/character (text) data (e.g. names)
• Alphanumeric data (a mix of letters and digits, e.g. A 00022)

(Date and logical/Boolean data are also acceptable types.)

(b) The four data types available in Table 2. Examining each field:

The four main data types present are therefore Alphanumeric (Student I.D.), Text/Alphabetic (Name and Gender), Date (Date of Birth) and Numeric (Score).

(a) Matching each ICT type with its relevant communication sector. The four sectors listed (Radio, Internet, GSM, video conferencing) belong to the ICT types as follows:

Reasoning: Broadcasting is the ICT used to transmit radio (and television) programmes; a data network carries traffic for the Internet; telecommunication covers voice/mobile telephony such as GSM; and satellite communication provides the long-distance links that make video conferencing possible.

(b) Three computing devices for each period:

(i) 19th century (1800s):

• Difference Engine (Charles Babbage)
• Analytical Engine (Charles Babbage)
• Hollerith's Tabulating Machine / punched-card machine (Herman Hollerith)

(ii) 20th century (1900s):

• Harvard Mark I
• ENIAC
• UNIVAC (and the personal/desktop computer)

(a) Definition of programming language

A programming language is a set of symbols, words and grammatical rules (syntax) used to write instructions that a computer can understand and carry out to solve a problem. Examples are BASIC, C, Java and Python.

(b) The expressions in BASIC notation

• (i) \(x(w + y)^2\) is written as X * (W + Y) ^ 2
• (ii) \(\dfrac{ab}{cd}\) is written as (A * B) / (C * D)
• (iii) \(p = 2(1 + b)\) is written as P = 2 * (1 + B)

(c) BASIC program to calculate the area (A) of a rectangle

The area of a rectangle is length multiplied by breadth, \(A = l \times b\).

10 REM PROGRAM TO FIND AREA OF A RECTANGLE
20 INPUT "ENTER LENGTH"; L
30 INPUT "ENTER BREADTH"; B
40 A = L * B
50 PRINT "AREA OF RECTANGLE = "; A
60 END

(d) Two levels of programming language

1. Low-level language (machine language and assembly language).
2. High-level language (such as BASIC, C, Java and Python).

(a)(i) Definition of Information and Communication Technology (ICT)

Information and Communication Technology is the use of computers, telecommunication equipment and related electronic devices, together with the necessary software, to gather, process, store, retrieve and transmit information from one place to another.

(a)(ii) Three uses of ICT in the banking sector

1. Automated Teller Machines (ATM): customers withdraw cash, check balances and transfer funds electronically without a cashier.
2. Online / Internet and mobile banking: customers operate their accounts, pay bills and transfer money over the Internet or a mobile app.
3. Electronic funds transfer and cheque/record processing: banks move money between accounts and keep customer records in databases, and use ICT for card payments and account statements.

(Other acceptable uses: electronic clearing of cheques, SMS/e-mail alerts, and a networked ledger shared among branches.)

(b) Full meaning of the acronyms

• LAN - Local Area Network
• GPS - Global Positioning System
• IP - Internet Protocol