Science universe: Physics articles

The social impact of computers Many businesses make use of electronic mail and electronic funds transfer to improve efficiency, reduce costs and speed up communication. (a) State one advantage of using electronic mail instead of having a telephone conversation. (b) Slate one difference between electronic mail and electronic funds transfer. (c) Name two applications that might use electronic funds transfer. (d) Describe how electronic mail and electronic funds transfer might change the work patterns and lifestyles of people using them. Many goods and services can now be paid for using plastic cards. All the card companies use computers to work out the bills each month. This means t.hat the card company computers store a lot of personal details about their customers and their purchases. If another organization got hold of the information it could be used against the card holder. (a) Give two different organizations that might want to have access to this personal informati...

Use of Computers in industrial processes A greenhouse has a window which can be opened or closed under computer control. It also has a heater which can be switched on or off by the computer. There is an electronic thermometer connected to the computer for measuring the temperature inside the greenhouse. It is a very hot day so the window is open and the heater is off. At night there is a dramatic fall in temperature. (a) How will the computer know about changes in temperature? (b) List the two steps that the computer will take as the temperature falls. A microprocessor system is used to control the heating in a house. The heating can be set to come on and off at particular times, and the temperature in each room can be individually set. Within each room there is a temperature sensor, and an electrically controlled valve to turn radiators on and off. (a) Explain why the converters are needed. (b) Discuss the advantages and disadvantages of using a computer controlled s...

Technical , Scientific and Other Uses A runner is training for a 1500 m race. The coach is worried about the effects of running on the althete's heart and lungs. To monitor the runner there is a microcomputer system worn on a belt around her waist. There are sensors that will measure the following: 1 Breathing rate. 2 Heart rate. 3 Stepping rate. These sensors are connected to the microprocessor. The microprocessor is connected to a radio transmitter. The transmitter sends the information collected to a track side computer system. This is shown in the diagram on the next page. (a) What inputs are required for this data logging system. (b) There is an output device connected to the belt microprocessor. This output device is not shown on the diagram. It gives urgent information to the runner. (i) Describe or name a suitable device. (ii) Give one use for this device. (c) The track side computer system also has an output device. (i) Describe or name a suitable d...

Communications Systems and Word Processing (a) Name a teletext service that is available through an ordinary television signal. (b) Name a widely used public View data service that uses the telephone network. (c) Apart from costs and equipment, describe two main differences between these two forms of videotext. (a) What is communications software? (b) When would communications software be used'? (c) Explain the difference between Ceefax/Oracle and Prestel. (d) Explain why you often need a modem to transmit data between computers over a telephone link. (e) Describe an application which would use communications software. (a) View data systems such as Prestel provide users with a wide range of information. The diagram on p. 203 shows the stages necessary for a user to access a particular page of information. Complete the flowchart by choosing suitable statements from the list provided.   Statements Enter page number Enter password Dial computer Load commu...

Jops in computing This is a list of jobs done by people working at the DVLC. Job 1: Loading magnetic tapes. Job 2: Altering the programs. Job 3: Entering data into the computer. Job 4: Managing the computer department. Which of the above jobs is done by (a) the computer operator? (b) the keyboard operator? Here is a list of job titles to do with computers: Computer engineer Data control clerk File librarian Programmer Shift leader Computer operator Data processing manager Keyboard operator Salesman Systems analyst For each of the tasks below, write down the most likely job title of the person doing it. You can use a job title once, more than once, or not at all. (a) Loading a line printer with paper. (b) Coding a computer program. (c) Appointing new staff in a Data Processing Department. (d) Correcting errors in a program. (e) Finding the correct data tape. (0 Testing a new computer system. (g) Demonstrating a computer to a new cust...

Processing system Which of these applications is an example of a real-time computer system? A Controlling a nuclear reactor B Printing wage slips C Producing gas bills D Searching a database A computer system with a single disc drive and printer allows up to 50 users simultaneous access. If two or more users attempt to print out reports at the same time, how would the system handle this? Write down the names of the units marked A, Band C on the above diagram of a microcomputer. These are all modes of computer operation. For each of the applications given below write down the most suitable mode of operation. (a) Controlling the signalling on an underground railway system. (b) Updating the accounts in a Building Society overnight. (c) A system to allow many students in a large Polytechnic access to the central database at the same time. Tick the three applications in the list which would be carried out using batch processing. ...

Software Description: Programs and procedures, with their documentation, which can be implemented on a computer system. Term: Excluding games and entertainment software, most commercially produced software is either an application package or a utility program. (a) (i) Give one example of an application package. (ii) Give one example of a utility program. (b) Any good applications package has these features regardless of the task it is to do. 1 It must be robust.. 2 In order to sell well it must be portable. 3 It must be reliable. Explain what each of the underlined terms mean. You may use examples to help you explain. CASE STUDY Ring one item from the following list to complete the sentence. an applications program a compiler a utility program an algorithm A program to sort the transaction file is called . Which one of the following is a systems program? A A stock control program B A spreadsheet program C A file-copying program D A graphics p...

files CASE STUDY Opposite each of the following statements ring whether it is true or false. statement Vehicle records are divided into fields true false Vehicle fields are divided into files true false Vehicle files are divided into records true false Vehicle records are divided into files true false Which of the following is suitable for storing in a fixed length field of 6 characters? A Address B Birthplace C Date of birth D Name A stock file is held on magnetic disc so that records can ...

Errors The T40 microcomputer system has a high level language interpreter. (a) (i) Explain how a syntax error can occur. (ii) Explain how you would find the syntax error. (b) (i) Give and explain an example of a logical error. (ii) Explain how to find the logical error. A program is executed and produces results which are found to be incorrect. List three different methods the programmer can use to locate a mistake in the program. A company records the workers clocking in and out times on time sheets. There is no night shift. The format for each sheet is: A five digit works number, followed by 5 or 6 pairs of times in 24 hour clock notation, (time of arrival followed by time of leaving), each field separated by a slash/. An example is shown below. It has three errors in it. 20023/0900/1703/170610859/0858/1659/090111702/08591170841090011330 (a) Find the three errors and draw a ring around each. (b) For each error give a validation rule that might be used in...

Programming-languages and styles A pupil has written a program. As it is in a computer language why does it need to be translated before the computer can execute it? (a) A high level language is slow to execute. (b) A high level language is easy for people to read and write. (c) This is because it is close to human language. Write three statements like these about a low level language. (a) Name a commonly used high level computer language. (b) Name the two different types of translators used with a high level language. (c) Explain the main difference between the methods of operation of these two types of translator. (d) What type of translator is used for a low level language? (e) What is the name for the type of instructions that the computer hardware actually uses? A program is written in a high level language. Which one of the following statements is true? A Each instruction in the program represents a number of machine instructions. B It is written in binary...

Using computers to solve problems A software house is planning to release a new accounts package for small businesses. The package is designed to do the following tasks: (i) Print out a bill for each order sent out by the business. (ii) Print out a payment slip to go with all bills paid by the business. (iii) Record the details of all the goods bought and sold by the business. (iv) Keep a record of all stock held, and update this record when goods are Sold or received. (v) Keep and update the financial records of the business, e.g. how much money is in the bank, how much is owed to the business, how much is owed by the business, profits, losses etc. (a) Give four essential items of hardware that would be needed to run this sort of package. (b) There are both advantages and disadvantages for small businesses in buying packages like this accounts package. State two advantages and two disadvantages, to a small business, of buying a ready made package from a software hous...

Storage Devices and Media Would the program for an automatic washing machine be held in RAM or ROM? (a) Write down what each of the following abbreviations stands for: (i) ALD. (ii) RAM. (iii) ROM. (iv) TAS. (b) Describe the difference between ROM and RAM, and give an example of the use of each. SEB Standord Specimen. Topic: Computer Systems (a)   Which computer has the larger random access memory and what size has it? (b) Most computers also have some ROM. Explain why ROM is needed. (c) A friend buys a NDCRON. As he types in a correct COMAL program he keeps getting error messages. Why might this be? Files held on disc have been compared to songs held on a long playing record and files held on magnetic tape have been compared to songs held on tape. Give one advantage of holding files on tape. Give one advantage of holding files on disc. Backing storage on most commercial computer systems uses either magnetic tape or magnetic disc. (a) (i) Which m...

output When Mrs Smyth's order is delivered to her door, the address label has been produced by the computer on 'Preprinted' stationery. (a) What is 'Preprinted' stationery? (b) Why is it more convenient to use preprinted stationery for these labels? All computer systems require at least one input device and at least one output device if they are to do a useful job. Below are three situations. Give an input device and output device for each. Situation (a) A microprocessor system in a washing machine. (b) An enquiry/booking system of a large airline. (c) An arcade video game. A computer program is written such that the user makes selections from a menu. Give two reasons, other than speed, why using a menu to select the commands might be better than typing in the commands themselves. A daisy wheel printer, a dot matrix printer, and a graph plotter could all be used to produce paper output from a computer. (a) A daisy wheel printer and a dot ma...

Data Preparation and Input A keyboard operator is entering information into a computer system. Information is read from the data capture forms and typed in. Describe a method of verification which would help to reduce errors. The following table contains a list of devices and media. Show whether each is used for input or output, by means of a tick ( √ ) in the correct column. Device/media Tick (√) input Tick (√) output Mouse Graph plotter Line printer Magnetic ink character reader Which one of the following devices is most likely to be used off-line to a main computer? A Magnetic tape unit B Disc drive C Key-to-d...