A Level Computer Science 9618 Paper 33, Oct/Nov 2023

Write the normalised floating-point representation of +65.25 in this system. Show your working. Mantissa Exponent Working

Explain the problem that will occur in storing the normalised floating-point representation of +65.20 in this system.

Draw one line to connect each protocol to its most appropriate use. Protocol: HTTP, BitTorrent, SMTP, IMAP Use: to provide peer-to-peer file sharing when retrieving email messages from a mail server over a TCP/IP connection when transmitting hypertext documents to map MAC addresses onto IP addresses when sending email messages towards the intended destination

Outline the purpose of the Link layer in the TCP/IP protocol suite.

Describe sequential and random methods of file organisation. Sequential file organisation ....................................................................................................... Random file organisation ..........................................................................................................

Outline the process of sequential access for serial and sequential files.

Complete the truth table for the given logic circuit.

Simplify the given Boolean expression using Boolean algebra. Show your working. $\mathrm{Y}=\bar{\mathrm{A}}\mathrm{.}\bar{\mathrm{B}}\mathrm{.}\bar{\mathrm{C}}\mathrm{.}\bar{\mathrm{D}}+\bar{\mathrm{A}}\mathrm{.}\bar{\mathrm{B}}\mathrm{.}\mathrm{C}\mathrm{.}\bar{\mathrm{D}}+\bar{\mathrm{A}}\mathrm{.}\mathrm{B}\mathrm{.}\bar{\mathrm{C}}\mathrm{.}\bar{\mathrm{D}}+\bar{\mathrm{A}}\mathrm{.}\mathrm{B}\mathrm{.}\mathrm{C}\mathrm{.}\bar{\mathrm{D}}$

A student buys a new computer. State one benefit to the student of a user interface and give an example. Benefit ...................................................................................................................................... Example ....................................................................................................................................

Two of the process states are the running state and the ready state. Identify one other process state.

Outline conditions under which a process could change from the running state to the ready state.

Complete the file handling pseudocode. The function Hash() takes the customer account number as a parameter, calculates and returns the hash value. DECLARE Customer : TAccount DECLARE Location : INTEGER DECLARE AccountFile : STRING .................................................................................................. "AccountRecords.dat" ............................................................... AccountFile .......................................................... OUTPUT "Please enter an account number" INPUT Customer.AccountNumber Location ← Hash( ..............................................................................................................) SEEK ..................................................................................................................... , Location ............................................................. AccountFile, .......................................................... OUTPUT Customer // output customer record CLOSEFILE AccountFile

Define the term exception handling.

State two possible causes of an exception.

Write the infix expression for this Reverse Polish Notation (RPN) expression: 5 2 – 5 4 + * 9 /

Show how the contents of the following stack will change as the RPN expression in part (a)(i) is evaluated.

Explain how a stack can be used to evaluate RPN expressions.

Write the pseudocode for the required declarations.

Complete the pseudocode function Pop() to pop an item from Stack. // popping an item from the stack FUNCTION Pop()............................................................................... DECLARE Item : REAL Item ← 0 ............................................................................... BasePointer THEN Item ← ............................................................................... TopPointer ← ............................................................................... ELSE OUTPUT "The stack is empty – error" ENDIF ............................................................................... ENDFUNCTION

Compare and contrast the queue and stack Abstract Data Types (ADT).

Anthony is a student who would like to study history and geography. Write additional clauses to represent this information. 22 ............................................................................................................................................. 23 ............................................................................................................................................. 24 .............................................................................................................................................

Using the variable X, the goal: choice1(X, chemistry) returns X = teresa, elspeth Write the result returned by the goal: choice1(X, mathematics) X = .....................................................................................................................................

Students must choose two different subjects such that: N may choose S, if N is a student and S is a subject and N has not chosen S as the first choice. Write this as a rule. may_choose_subject(N, S) IF ............................................................................................................................................. ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................