Validation

A validation program checks whether data is accurate, complete and reasonable before processing. E.g. range check.

Random Access memory (RAM)

Temporary storage of data which can be read from and written to. It is volatile, data is lost when computer is switched off; so save your work before you switch off the computer.

Job control language

It is used to identify the job and its requirements to the operating system e.g. which program to be loaded and which file to be copied. It is used in batch processing for payroll and billing.

Interrupt

A signal activated when an event of some type occurs that, as a result, stops a program from executing. The task with a higher priority is carried out first and the task with the lower priority will be put on hold. For e.g. if one workstation is saving while the other is printing, the printing would be put on hold and the saving will be done first.


Stepwise refinement

Breaking down a problem into smaller sub-problems. E.g. The algorithm to display sum of two numbers can be broken down into 3 modules i.e. Input the two numbers, calculate sum of the two numbers and display the sum.

 

Two items that could be imported into a word-processed document are:

Graphic files or Cliparts

Charts from a spreadsheet program

Digitising text from magazines, newspapers, etc.

Two ways of importing these items into a word-processed document are:

Select the text or objects, Cut and paste them in the word-processed document

Select the chart, click Copy, switch to word document, click in the document, paste the chart into word document.

Use a scanner to scan the text or picture to be included into a word-processed document

 

A compiler converts high-level language into machine code whereas an assembler converts assembly language into machine code.

Three tasks that an operating system carries out are:

Controlling the peripherals or hardwares

Managing memory resources

File management e.g. ensuring files are copied, read or saved properly

Error handling e.g show warning messages when the user did something wrong.

A gardener has installed a microprocessor-controlled system in a greenhouse to control the air temperature.

Two advantages of this system for the gardener are:

The computer system would open and close windows automatically

Adjust the heater automatically

Turn the sprinkler on and off automatically

A suitable input device is temperature sensor or humidity sensor

A suitable output device is heater, actuators to open/close window and actuators to switch sprinkler on/off.

Two devices used by disabled people to access computer systems are:

Voice recognition input device

A head pen

(a)(i) B2

(ii)E2

(b)(i) E2 = D2*100/B2

(ii)Select cell E2, right click on the mouse and change the format of the cell to Number with one

decimal place

Shade A1:C6

(i) DOORS

(ii) MAKE

Two additional fields that could be added are:

COLOUR

PRICE

M412, F214, F219

REF can be used as a keyfield. It is unique, therefore it can be used to identify a particular record.

F214, F219, T517, R317, C615

(a)

(b)Repeat 4 [Forward 40, Right 90]

(c)Use a variable (L) to store the length of square to be drawn

Input L

Repeat 4 [Forward L, Right 90]

(a)

Two benefits to the bookseller of using the Internet to sell books are:

The bookseller could sell the books to customers around the world

Cheaper, as business can be done at home and there is no need to give out brochures.

(a) A system analyst could investigate the problem by interviewing the users, studying existing documents, observe how the job are carried out and asking the users to fill up questionaires. He could then propose a solution by:

Specifying the software requirement

Specifying the hardware requirement

Designing the User interface

Designing the structure of the file

Two possible effects on the staff when a computer system is installed are:

Re-training

Unemployment

 

 

(a)Two validation checks that the system should do on the customer account number to ensure that the correct record is accessed are:

Check digit to check that all the digits in the account number are copied correctly

Field length check to ensure that the correct number of characters are present in the account number entered

(b) State two reasons why the amount of money in the account may not be correct.

The bank teller keyed in wrongly the amount of a cheque issued by the account; this can be clarified by looking at the previous day’s balance before the cheque was cleared. Transposition errors could occur e.g. typing $26179 instead of $21679

Money debited from the wrong account because the bank teller keyed in the wrong account number.

Three data protection rules that could apply to the data in the customer records are:

People have the right to see and correct the data stored about them

Data held on the people must be relevant

Data must not be held longer than is necessary

(a) Three features that are available on the CAD system are:

3D views

Objects can be rotated and reflected without redrawing

We can zoom in to have a closer view of a cross section

(b) Two advantages for the factory of using the CAD software rather than producing the designs manually are:

Drawings are more accurate

User can experiment with a variety of solutions

(a) Laser light to read the data on a bar code.

(b) The computer compared the code read by the bar code reader with a stored table and then output the price and the description.

(c) The system would produce an order automatically. Using the supplier code which is stored in the item’s record, a link is established with the supplier’s file to retrieve and print out the supplier’s address.

(d) Two precautions that should be taken to prevent loss of data due to system failure are:

Keeping backups

The system is protected by an UPS(Uninterruptable Power Supply)

Input a Number

Smallest = Number

Count=1

Repeat

Input a Number

Count = Count + 1

If Number < Smallest then

Smallest = Number

End if

Until Count = 10

Output Smallest