WAEC SSCE - Computer Studies - 2021 (Essay)

(a) Convert \(AB1_{16}\) to the Octal system

Step 1: Write each hexadecimal digit as 4 binary bits.

\[A=1010,\quad B=1011,\quad 1=0001\]

\[AB1_{16}=1010\,1011\,0001_2\]

Step 2: Regroup the binary digits in threes from the right.

\[101\;010\;110\;001\]

Step 3: Convert each group of three to its octal digit.

\[101=5,\;010=2,\;110=6,\;001=1\]

\[\therefore AB1_{16}=5261_8\]

(b) Convert \(1110111.101_2\) to the Denary (base 10) system

Integer part, using place values \(64,32,16,8,4,2,1\):

\[1110111_2=64+32+16+0+4+2+1=119\]

Fractional part, using place values \(\tfrac{1}{2},\tfrac{1}{4},\tfrac{1}{8}\):

\[.101_2=1(0.5)+0(0.25)+1(0.125)=0.625\]

\[\therefore 1110111.101_2=119.625_{10}\]

(c) Convert \(507_8\) to the Binary system

Since the digit 7 is not valid in base 2, the number is in the octal system. Write each octal digit as 3 binary bits.

\[5=101,\quad 0=000,\quad 7=111\]

\[\therefore 507_8=101\,000\,111_2=101000111_2\]

Check by way of denary: \(507_8=5\times8^2+0\times8^1+7\times8^0=320+0+7=327_{10}\), and repeated division of \(327\) by 2 gives \(101000111_2\), confirming the result.

(a) What are "Reports" in a database system?

A report is a database object used to organise, summarise and present data from one or more tables or queries in a formatted, printable layout. Reports are designed mainly for output: they allow the user to arrange records neatly, group and sort them, perform calculations such as totals and averages, and produce professional printed documents such as invoices, result sheets or mailing lists.

(b) Four ways in which reports can be viewed in a database management system (MS Access):

1. Report View - shows the finished report on screen as a continuous view.
2. Print Preview - shows exactly how the report will look when printed, page by page.
3. Layout View - shows the report with live data while allowing you to adjust the design and column widths.
4. Design View - shows the underlying structure (sections such as header, detail and footer) for detailed editing of the report.

(c) Steps to print a report in MS Access:

1. Open the database and, in the Navigation Pane, locate and open (or select) the report you want to print.
2. Switch to Print Preview to confirm the layout, page size and orientation are correct.
3. Click the File tab (or the Office/Backstage button) and choose Print.
4. In the Print dialog box, select the correct printer and set the options (number of copies, page range).
5. Click OK (or Print) to send the report to the printer, then collect the printout.

(a)(i) Universal Serial Bus (USB):

Universal Serial Bus (USB) is a standard plug-and-play interface used to connect a computer to peripheral devices such as keyboards, mice, printers, scanners, flash drives, cameras and mobile phones for communication, data transfer and power supply.

(a)(ii) Benefits of USB connection:

• It supports plug-and-play; connected devices are automatically detected and configured.
• It allows data transfer and can also supply low-voltage power to devices through the same cable.

(b) Identification and category of storage devices:

Universal Serial Bus (USB) is a standard plug-and-play interface used to connect a computer to peripheral devices such as keyboards, mice, printers, scanners, flash drives, cameras and mobile phones for communication, data transfer and power supply.

(a)(ii) Benefits of USB connection:

• It supports plug-and-play; connected devices are automatically detected and configured.
• It allows data transfer and can also supply low-voltage power to devices through the same cable.

(b) Identification and category of storage devices:

REM Program to grade scores
CLS
DO
    INPUT "Enter a score (negative to stop): ", SCORE
    IF SCORE < 0 THEN
        EXIT DO
    END IF
    IF SCORE < 50 THEN
        PRINT "Poor"
    ELSE
        PRINT "Satisfactory"
    END IF
LOOP
END

CLS
Start:
INPUT "Enter a score: ", SCORE
IF SCORE < 0 THEN END
IF SCORE < 50 THEN PRINT "Poor" ELSE PRINT "Satisfactory"
GOTO Start

REM Program to grade scores
CLS
DO
    INPUT "Enter a score (negative to stop): ", SCORE
    IF SCORE < 0 THEN
        EXIT DO
    END IF
    IF SCORE < 50 THEN
        PRINT "Poor"
    ELSE
        PRINT "Satisfactory"
    END IF
LOOP
END

CLS
Start:
INPUT "Enter a score: ", SCORE
IF SCORE < 0 THEN END
IF SCORE < 50 THEN PRINT "Poor" ELSE PRINT "Satisfactory"
GOTO Start

OK

OK

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