Information Processing

Introduction

• Definitions of hardware, software, package, program, data, parameter.
• Overview of the range of computers currently used from lap-top to supercomputer.
• Configuration diagram showing how the components of a computer system are related. Difference between control signal and data flow.

Input

• Review of methods of data capture to include OCR, OMR, MICR, barcodes, text/image scanners, magnetic stripe, voice, touch screen, keyboard, and concept keyboard.
• Advantages and disadvantages of these methods of data capture when compared with others. In particular, a comparison of speeds, costs, user involvement, accuracy of the data received by the computer.
• Choose the best data capture method for a given application.
• Conditions required for each of these data capture devices to be used. A detailed explanation of the internal operation is not required.

Data Checking

• Difference between validation and verification.
• Validation checks – range, data type, presence, sequence.
• Specifying the validation possible for a given set of data.

Check digit systems – normally using modulo-11 and weights 6,5,4,3,2,1 etc.

• Specify which data can/should contain check digits.
• State the guarantees that check digit numbers provide.
• Calculate the check digit for a given number.
• Validate a number which contains a check digit.
• The use of “X” as a check digit.

Output

• Ways in which data can be represented – tables, lists, summary statistics, charts, textual reports.
• Name the range of printers currently available – laser, ink jet.
• Advantages and disadvantages of different types of printers.
• Screen output. Its limitations.
• Identifying whether screen or printer would be more suitable for a given application.
• Types of plotters currently available. Comparison with printers.
• Identifying whether a printer or plotter would be more suitable for a given application.
• Other forms of output. COM. Microfiche. Applications where these might be used.

Processor

• Component parts of the CPU and their functions – ALU, control unit.
• Main memory and its various forms – RAM, ROM, cache, special purpose RAM e.g. for VDU.
• Name registers in general use – accumulator(s), program counter (PC), memory address (MAR), memory data/buffer (MDR/MBR), current instruction (CIR).
• Bus structures.

Fetch-execute cycle.

• Name the steps an instruction passes through in the cycle.
• Identify how the registers are used for basic instructions.
• e.g. LDA Price, SUB Tax. This topic must be covered in detail.

Software

• Distinction between system software and application software.
• Distinction between general purpose and special purpose software. Understand that the USER dictates how general purpose software is used.
• Outline of features of operating systems including systems with multiprogramming facilities. Name different operating systems currently in use and compare in outline.

 System software

• File management software.
• Utility software. Sort file. Merge files.
• Language translators. Assembler, compiler, interpreter – basic differences.

Filing Systems

• Review of current storage devices – diskette, hard disc, Winchester, flash drive/pen stick, optical devices, digital versatile disk, tape and cassette.
• The need for buffers and their role in data transfer.
• Definitions of storage terms – file, record, field, cylinder, track, sector, header label, inter-block gap. Distinction between storage device and storage medium.
• The structure of data stored on a storage medium.
• Data transfer checks. Parity and its purpose. Describe odd/even parity with specific numeric examples illustrating acceptance/failure. Cyclic redundancy check.
• Sequential master file update using an unsorted transaction file. Labelled system flow chart for this process.
• Selecting the most appropriate file organisation for a given application.

File Organisation and file access

• Define organisation types – serial, sequential, indexed sequential, random.
• Distinction between organisation and access. Examples of a file being accessed in more than oneway.
• For indexed sequential organisations – an understanding of up to 2-levels of indexing.
• Appreciation that not all record keys appear in the index. How any record can be accessed.
• Overflow areas.
• For random access – hashing algorithms. Develop a simple algorithm for a given situation.
• For each of the four organisation methods, describe the program sequence of steps to: (a.) access a single record from the file. (b.) add a new record to the file. (c.) delete a record from the file.

Processing

• Different types of processing – batch and real-time.
• The role of batch processing with today’s sophisticated systems. Examples of batch processing currently in use.
• Real-time systems – examples of current use.

Security and Privacy

• Security defined as the safeguard of hardware, software and data.
• Distinction between security and privacy.
• Realistic methods of data security – securing against: (a.) accidental damage or loss of data. (b) deliberate sabotage.
• Methods of achieving good privacy of data.
• Determining the security/privacy required for a given situation.