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ExamQuestions and Answers
What is meant by the SDLC? - ANSWER Describes the various stages in designing and implementing a new computer system What are the major elements of the SDLC - ANSWER Information gathering, feasibility study, analysis, design, implementation (development), testing & evaluation What is the waterfall model? - ANSWER Each stage of development flows from the previous one, feedback to the previous stage takes place independently of forward flow (you can backtrack) What is meant by agile methods of development? - ANSWER A system made from small software modules What is meant by extreme programming? - ANSWER A form of agile development, that partners programmers together, often including a user to help the process What is meant by the spiral model of development? - ANSWER There are four distinct quadrants, analyse, design, implement & evaluate. It is an iterative process, each successive loop around the spiral refines the prototype, until the project is finished What is RAD - ANSWER Rapid Application Development, uses short bursts of development, usually ending in prototypes that are then shown to the end user Which method is best suited to large, high risk projects? - ANSWER Spiral Which development method is best suited to a project were the user is unsure of what they want? - ANSWER Extreme / RAD Which development method is best suited to small projects? - ANSWER Waterfall What is meant by application software? - ANSWER A program that allows a user to achieve a task What type of app is best suited to essays? - ANSWER
What type of application is best suited to storing (and interrogating) large amounts of data? - ANSWER Database What is stored in the MDR? - ANSWER The data or instruction to be decoded What is stored in the MAR? - ANSWER The address of the memory location currently in use What is stored in the PC? - ANSWER The address of the next instruction to be executed What is stored in the Current Instruction Register? - ANSWER Holds the instruction whilst it is being decoded What is stored in the accumulator? - ANSWER the results of calculations processed by the CPU What happens in the fetch part of the cycle? - ANSWER PC to MDR, Increment PC, Load data in MDR, load instruction into CIR What happens in the decode? - ANSWER CU splits the operation & operand, address is placed in MAR OR actual data copied to MDR & passed to ALU What happens in the Execute? - ANSWER Actions the instruction What does the Address Bus do? - ANSWERPoints to the address currently in use (either as STA or LDA) What is the purpose of the Data Bus? - ANSWER Data/instructions are sent along the data bus What does the Control Bus do? - ANSWER Receives signals from all parts of the computer and coordinates components What does FDE stand for? - ANSWER Fetch, Decode, Execute What is the purpose of the ALU? - ANSWER To deal with all mathematical & logical calculations What does function does the CU have? - ANSWER Controls the flow of data and coordinates other units What do the registers do? - ANSWER A single item of data is
What does MIMD stand for? - ANSWER Multiple Instruction Multiple Data What does SISD stand for? - ANSWER Single instruction Single Data What type of processing uses SISD? - ANSWER Von Neumann, Scalar Processing What type of processing uses MIMD? - ANSWER Multiple cores, parallel processing, each core carrying out different tasks What type of processor uses SIMD? - ANSWER Array (Vector) processors Data stored as what type of media e.g. floppy, hard drive - ANSWER Magnetic Data stored as what type of media e.g. CD-ROM, DVD - ANSWER Optical Which storage device would be best for storing and sending wedding photos through the post? - ANSWER DVD, CD- ROM Which storage device would be best for backing-up data - ANSWER Portable HDD, Magnetic Tape, Cloud Name two input devices designed for accessibility - ANSWER Puff-suck switch, Foot Mouse, braille keyboard What input device is regularly used for entering the price of goods in retail? - ANSWER Bar code scanner A train operator controls trains from a central office. What input devices might be helpful? - ANSWER Mouse, keyboard, touchscreen, microphone A train operator controls trains from a central office. What output devices might be helpful? - ANSWER Monitor, siren, warning lights What is virtual memory? - ANSWER the use of the secondary storage as part of the memory when RAM runs out What is an actuator - ANSWER A device controlled by a computer, that can cause physical movement Describe round robin scheduling - ANSWER "each user
Describe system of priorities scheduling - ANSWER highest priority first Describe the scheduling method that is dependent length of job scheduling - ANSWER shortest job first jobs processed in order of arrival, is known as what? - ANSWER first come, first served scheduling features of utility programs in an operating system, include... - ANSWER "maintenance program/carries out housekeeping e.g. Virus checker" - ANSWER Name 2 features of data security in an operating system - ANSWER passwords ,access rights "use of encryption" - ANSWER Name two features of an operating system - ANSWER Error reporting, Memory management, Resource management, I/O management, Device management, Interrupt management, User interface(s), File Allocation Table (FAT), Boot File What is meant by application Software? - ANSWER specific computer tasks. Enables you to perform What is the purpose of Document Production Software?
- ANSWER of features that assist you in writing and formatting documents. Has a variety What is the purpose of Spreadsheet Software? - ANSWER graphs For calculations &
What is a firewall? - ANSWER Controls who gets into your computer from the Internet or other network connection, by inspecting packets of data. What is the purpose of Utility Programs? - ANSWER To customize the way the computer behaves, making it more efficient or easier or safer to use. What is source code? - ANSWER High level language, such as C#, Python etc What is object code? - ANSWER (often displayed as HEX) Compiled high level code, machine code, binary What is assembly code - ANSWER low level language, one-to-one relationship with machine code, architecture dependant What are the ways of running source code? - ANSWER Interpreter & compiler What are the stages of compilation? - ANSWER Lexical analysis, syntax analysis, semantic analysis, code generation, optimisation What does TELOS stand for? - ANSWER Schedule Technical, Economic, Legal, Operational, What document concludes the Feasibility study? - ANSWER Feasibility report Name two methods of investigation - ANSWER meetings, existing documentation Observation, interviews, surveys,
Describe the spiral model - ANSWER improvements made each time Repeats from analysis to evaluation, Describe the waterfall model - ANSWER Each step can be returned to What are the advantages of the spiral model? - ANSWER projects & Large projects" "Well suited to high risk A AND 0 - ANSWER 0 What are the disadvantages of the spiral model - ANSWER expensive Risk analysis is What is the advantage of the waterfall model - ANSWER Easy to manage What is a multi-user OS? - ANSWER Allows several people to access the system What is a multi-tasking OS? - ANSWER concurrently Allows several programs to be run Distributed processing is...? - ANSWER to solve one task (e.g. SETI) Combining a group of computers in order What is an embedded system? - ANSWER Likely to have only one job, built into devices that are not traditional computers e.g. TV, washing machine A real time system...is? - ANSWER Designed to carry out actions in a guaranteed
What is meant by OPCODE? - ANSWER Opcode - (mnemonic part of instruction) indicating what it is to do e.g. SUB What is meant by OPERAND? - ANSWER Operand - address field in instruction/holds data or address to be used e.g. 34 What type of task is best suited for an Imperative language? - ANSWER When tasks can be broken into in blocks - proc & funcs Programs state what to do & how to do it
- What type of task is best suited for a declarative language? - ANSWER problem consists of declarations/statements or facts/rules "•Whe n a What type of task is best suited to a high level language? - ANSWER When mathematical functions are used Portability When there are library routines available When it's a complex problem What type of task is best suited for a low level language? - ANSWER "When there is limited memory e.g. in an embedded system What is a Mnemonic? - ANSWER commands Programming code / Shortened versions of What is a feature of a low level language? - ANSWER of the CPU?Can be very efficient" "Excellent for close control What is a disadvantage of using a low level language?
- ANSWER to use Can be difficult
What are the two major families of programming paradigms? - ANSWER Declarative and Imperative What is meant by a method? - ANSWER Associates routines, the equivalent of subroutines What is meant by an object? - ANSWER An instance of a class What is meant by a class? - ANSWER A template for a set of objects What are attributes? - ANSWER database) The data in an object (equivalent to fields in a What is meant by a derived class? - ANSWER from a parent/super class A class that has inherited properties What is meant by inheritance? - ANSWER methods of another, parent class The ability of a derived class to use the What is meant by direct addressing? - ANSWER without alteration Uses the data in the address field Describe immediate addressing - ANSWERuses the address in the address field, NOT as an address, but as a constant that is needed by the program Describe indirect addressing - ANSWER uses the address field to hole the address of a location that contains the required address
dictionary encoding How does runlength encoding work? - ANSWER Where a characeter is repeated several times it is recorded as one character and then the number of times it occurs How does dictionary encoding work? - ANSWER A dictionary of common strings is created and these are then referenced (with a number) in the main text What is encryption? - ANSWER the key Disgusing data so that it can only be read with What is asymmetric encryption? - ANSWER encrypt/decrypt the data A pair of keys is used to What is symetric encryption? - ANSWER both parties must have the same key A single key is used to encrypt the data, What does SQL stand for? - ANSWER Structured query language What is a flat file database? - ANSWER A database with only one table Describe a Format Check (picture check) - ANSWER checks the pattern of the data e.g. postcode LL99 9LL A form of validation that What is a presence check? - ANSWER A form of validation that means that data must be entered, usually used for the index, ID field
What is a type check? - ANSWER A form of validation that restricts the type of data being entered, e.g. only numbers What is a range check? - ANSWER A form of validation which allows values between an upper and lower range Describe a lookup check - ANSWER A form of validation. Data must be within certain limits/ selected from a list of alternatives What is a database - ANSWER A persistent, organised store of data Define an entity - ANSWER A real world object about what we store data Define a record - ANSWER A row of fields about one entry in the table Define a field - ANSWER A single piece of data in a record What is meant by Atomicity? - ANSWER OR not at all A transaction is completely carried out What is meant by Consistency? - ANSWER A transaction must take the database from one valid state to another valid state Define a primary key - ANSWER cannot be repeated. A unique field which identifies the record and What does ACID stand for? - ANSWER Atomicity, Consistency, Isolation,
Give 2 tasks that the DBMS allows us to do. - ANSWER Protect data, run queries to extract data, keep data consistent, keep data accurate What is the best validation for quantity of items ordered?
- ANSWER check e.g. 0 < x < 100 Rang e What is the best validation for date of birth - ANSWER range check e.g. <NOW() A database has 3 tables that are linked, this is known as a... - ANSWER Relational Database What is data mining? - ANSWER Searching through large amounts of data to find trends / make predictions that help decisions Internal (physical) view - ANSWER on the disk Show how the data is actually stored as bytes What does SQL stand for? - ANSWER Standard Query Language List 2 tools provided by the DBMS - ANSWER Modules Tables, Forms, Reports, Queries, What is the External view in a database? - ANSWER database (using forms etc) The user friendly view of the What is the Conceptual (logical) view, of a database? - ANSWER The view of the database used by the database designer showing how tables are constructed and
linked together Why would we need a foreign key in a table? - ANSWER To link 2 tables together in a relational database. It acts as a bridge between the tables. Is double entry a form of Validation or Verification?
- ANSWER Verificatio n Define a peer-to-peer network - ANSWER All computers are equal, they serve the needs of the user as well as carrying out network functions State 2 different LAN topologies - ANSWER Bus, Ring, Star What is the following type of network: One or more servers providing services to many clients - ANSWER Client-Server network What type of software is needed for a computer to communicate with a device such as a printer - ANSWER Device driver - driver software What language are websites generally written in?
- ANSWER HTML or HTML This device sends packets to every machine connected to it - ANSWER Hub State 2 differences between a LAN and a WAN - ANSWER LAN is over a small geographical area, whereas a WAN is over a large geographical area. LAN uses cables/wireless to transfer data, whereas a WAN uses telephone system etc. What does LAN stand for? - ANSWER Local area network
What are the disadvantages of a serial file? - ANSWER Searching must be one record after another, if the record is not present the whole file must be read What are the advantages of a serial file? - ANSWER new records Quick to create, easy to add What are the advantages of a sequential file? - ANSWER file. Searching is quicker, when it has been sorted You can sort a seqeuntial What a fixed length field - ANSWER length A field with the same number of bytes in What is a variable length field - ANSWER (dependent of the size of the data) A field with flexible field lengths What are the advantages of a fixed length field? - ANSWER programmers (you know were each field starts and ends) Much easier for What are the disadvantages of fixed length fields? - ANSWER They can waste space. Records could be truncated. What are the advantages of a variable length field?
- ANSWER the data - no wasted spaces Field sizes refelect What are the disadvantages of variable length fields?
- ANSWER difficult to program. They need an ""end"" character" "They can be What is a secondary key? - ANSWER A non unique field that can be indexed
What is the physical view? - ANSWER storage medium How the data is actually recorded on the What is the Logical view - ANSWER the tables, queries, reports etc Is the view of the structure of the database, What is the Users view (the external view) - ANSWER appearance and functionality of the database The user interface, the What does CRUD stand for? - ANSWER Create, Read, Update, Delete What is data integrity? - ANSWER The accuracy of the data What is data consistency? - ANSWER That the same data is viewed at all times Why have a network? - ANSWER distribution, availability Security, sharing resources, software What is the purpose of a router? - ANSWER It connects networks. Receiving data packets from one network and passing them to another. What is a topology? - ANSWER A physical layout for a network What physical elements are unique to a BUS topology?
- ANSWER terminators Main cable &
