Compu$-$Tech Computer Repairs

Compu$-$Tech is a computer repair company operating out of a small workshop. The owner, Lee is the

only person working in the company but he hopes to expand and employ more engineers in the near

future. At present Lee holds much of the information about repair jobs in a filing cabinet but this is rather

disorganised and he realises that a computer system would be a better method especially as any new

members of staff would also need access to this information.

When a customer brings in a faulty computer Lee logs the fault and the customer$$s details giving him$/$her

an estimated date for the repair to be completed. Every day he checks the list of repairs and selects the

jobs to be done that day. If he finds he doesn$$t have the required parts in stock for a repair he places a

purchase order with his supplier and reschedules the job to a later date. When a repair is complete and

the customer comes to collect the computer, Lee gives him$/$her an invoice and the customer pays

immediately.

Once a week Lee checks his stock of parts, and orders any that are getting low from his supplier.

a$)$ Explain the differences between a physical and a logical data flow diagram $($DFD$).$

$[6$ marks$]$

b$)$ Identify the processes, data stores and the external entities that you would include on a top level

data flow diagram $($DFD$)$ of the Compu$-$Tech company. $[5$ marks$]$

c$)$ Draw the context diagram and level $1$ DFD for Compu$-$Tech. $[14$ marks$]$

d$)$ Produce a Use Case diagram for the Compu$-$Tech system. $($NB: Additional marks for the correct

use of $<>$ or $>$ relationships$).[10$ marks$]$

e$)$ List FIVE principles of user interface design. $[5$ marks$]$