4f exam 2002

Some Answers to this years 4F (first year of IGCSE)
Information Technology IGCSE exam (International School the Hague)

Question

Answer

Points

Mention 3 different validation checks which can be used on an order code number like: 0947251839

Length check - all code numbers should have 10 digits (for example also valid for a dutch telephone number)
Range check - the order number should be in between 1 and 999999999
Availability check - check if the order number is available in the database system
Check-sum (Check Digit) - check (calculate) the total of the orders by hand and compare with the computers calculation
Data-Type-Check -> see if they are all numbers
6

What is a check-sum?

Checksum is a technique used by some communications protocols to check for errors in the information that has been transmitted over the wires. The numbers of bits, or electronic units, of information, is added up (summed) before it is sent. Then the protocol sends that sum along with the data. When the receiving computer gets the data, it counts the bits and checks it with the sum that was sent along. If the two sums don’t match, there was probably an error in the transmission (meaning the data transmission will have to be done one more time).
2

Describe three different tasks that could be performed by a computer operating system.

1. Open a file that is stored on the harddisk (the OS knows where to find it!)
2. Allow to choose a printer from a list of available ones
3. Change the name of a file that is saved somewhere
4. See (list) a directory of Files on a Floppy disk
5. Allows to Start programs (software) that are stored on your computer.
6. Allows to Start (or Shut down) the computer
7. Connects to a network (e.g. Internet)
8. Can detect new hardware devices connected (e.g. scanner)
3

What is a multimedia system?

A system that makes use of:
- sound
- CD-ROM
- graphics display
- often also a GUI operating system
- capable of showing video on the screen

Often used for playing games, but also great for browsing e.g. encyclopedias!
2

What is Assembler?

Assembly code is a low level programming language. Assembler contains instructions that are based on a specific CPU.
That means that there are several assembler versions, they are different for different CPU’s (like Intel, Motorola etc.)
An Assembler is the compiler, that will translate the assembly language into machine code (binary code), so the program can run on the specific CPU (computer)
example: Store 4, Load 3, Add 4, Print 3 (the numbers determine the registers = storage places in the CPU)
2

What is RAM?

RAM is random access memory. It is memory that can be changed or altered, it can be used for storing data.
You can find RAM as part of the Mainstore in any CPU, where it is used to store the programs (and data) that actually run on the computer. The more RAM you have, the bigger the programs can be that you can use (or more at the same time!)
RAM in the CPU are silicon chips.

RAM as Backstore would be e.g. a harddisk. They can store a lot of data, up to 40 Gigabyte nowadays. You can write and delete data on RAM-devices.
2

Explain, using examples if appropriate.
interpreter

An interpreter translates (compiles) a high level programming language (a source) into a machine orientated language (machine code). It does this translating line by line (one line stores one line of computer code). By doing so, it will stop as soon as an error is detected. The process is fast, but it will not generate a whole ‘overview’ of the translating.
Example: GW-Basic
Nowadays compilers are preferred.
3

What is a Barcode?

A barcode is a set of bars / stripes, they can be found as printed labels on articles in a shop. They stand for e.g. an Article number, or an ISBN book number.
The barcode contains the unique key-field (e.g. the article number) and the price and description of the article will be looked up in an (attached) database.

2

A hospital uses a computer system to store details about the patients.
(a) List three fields that would be in a patient's record, in addition to their name and address. [3]
(b) The doctors read the patient medical histories on their computer screens before treating the patients.
(i) Describe two checks that should be done by a doctor to make sure that they have the correct patient record on the screen.
(ii) State the type of file access that would be used by this system and give a reason why.
file access
reason why [2]
(c) Patient records will need to be amended, deleted and inserted. Give an example of why each of these would need to be done.
amended
deleted
inserted [3]
(d) Describe three data protection laws that may apply to patient data. [3]
(e) Describe two additional tasks that the hospital computer could do. [2]

a) Birthdate / patient-ID / Insurance company / Gender

b) Ask the patient in front of him for his Birthday (and compare to the one on the database screen)

b i) Load the picture of the Patient and compare to the person in the room.
b ii) random data acces (=direct data access)
It allows a fast data lookup, data is stored randomly, the Operating System keeps track of each stored item of data.
(study remark: compare acces with serial access = slow)

c) amended: when a field of a patient needs to be changed (e.g. their address)
deleted: when data is no longer needed (patient moves away, dies :-(
inserted: when a new patient comes into the hospital

d)
Patients may always know about the data stored
Patients have the right to (let) change data that appears to be wrong
Patients data may only be stored for medical purpose
Patients data may not be shared with unauthorized bodies (crosslinking)
Patients data may only be stored as long as needed.
10

What is serial access?

It’s a way of reading / writing records one after another (also called sequential). The medium used for this access method is Tape or Cassette. It’s used for long-term storage, as the tape is cheap to use, but data access reading time is high (slow to use).
Tape storage is used mainly by banks and insurance companies that need to keep data for a very long time (because of legal reasons, think about bank accounts, life insurance policies)
2

What is Batch processing?

It’s when all input data is collected before hand (and stored in data input files). The processing is done all in one go (a so-called Batch). The output is usually another big file and printed reports (also error listings if something went wrong).
Examples are the processing of electricity bills or salary (payroll) slips at the end of a month or year.
2

Put the following in order (it starts with investigate):
investigate
review / analyse / implement / design

investigate
analyse
design
implement
review
It’s called the ‘programming life cycle’
2

Why are check-digits used?

It allows to check if input data was entered correctly. A check-digit can be attached to (e.g.) a barcode. If the scanning goes wrong (maybe the label is damaged or dirty) the check-digit check will cause the computer to display an error message (instead of accepting the wrong input data! -> think about the wrong price scanned at a supermarket!)
1

Describe a computer system suitable for a school’s library.

It will consist of
Hardware:
a networked system (LAN) with several computers. They could be PC’s or Workstations. They will all be connected to the Database file server.
a network printer (laser quality)
a Barcode scanner (to scan students ID and Book labels)
a Receipt printer (for confirmation of borrowed items and paid fees)
Software:
a Central database system. It can be tailor made or bought ready-from-the-shelve
a Backup system (to make regular data backup’s)

3

Question	Answer	Points
Mention 3 different validation checks which can be used on an order code number like: 0947251839	Length check - all code numbers should have 10 digits (for example also valid for a dutch telephone number) Range check - the order number should be in between 1 and 999999999 Availability check - check if the order number is available in the database system Check-sum (Check Digit) - check (calculate) the total of the orders by hand and compare with the computers calculation Data-Type-Check -> see if they are all numbers	6
What is a check-sum?	Checksum is a technique used by some communications protocols to check for errors in the information that has been transmitted over the wires. The numbers of bits, or electronic units, of information, is added up (summed) before it is sent. Then the protocol sends that sum along with the data. When the receiving computer gets the data, it counts the bits and checks it with the sum that was sent along. If the two sums don’t match, there was probably an error in the transmission (meaning the data transmission will have to be done one more time).	2
Describe three different tasks that could be performed by a computer operating system.	1. Open a file that is stored on the harddisk (the OS knows where to find it!) 2. Allow to choose a printer from a list of available ones 3. Change the name of a file that is saved somewhere 4. See (list) a directory of Files on a Floppy disk 5. Allows to Start programs (software) that are stored on your computer. 6. Allows to Start (or Shut down) the computer 7. Connects to a network (e.g. Internet) 8. Can detect new hardware devices connected (e.g. scanner)	3
What is a multimedia system?	A system that makes use of: - sound - CD-ROM - graphics display - often also a GUI operating system - capable of showing video on the screen Often used for playing games, but also great for browsing e.g. encyclopedias!	2
What is Assembler?	Assembly code is a low level programming language. Assembler contains instructions that are based on a specific CPU. That means that there are several assembler versions, they are different for different CPU’s (like Intel, Motorola etc.) An Assembler is the compiler, that will translate the assembly language into machine code (binary code), so the program can run on the specific CPU (computer) example: Store 4, Load 3, Add 4, Print 3 (the numbers determine the registers = storage places in the CPU)	2
What is RAM?	RAM is random access memory. It is memory that can be changed or altered, it can be used for storing data. You can find RAM as part of the Mainstore in any CPU, where it is used to store the programs (and data) that actually run on the computer. The more RAM you have, the bigger the programs can be that you can use (or more at the same time!) RAM in the CPU are silicon chips. RAM as Backstore would be e.g. a harddisk. They can store a lot of data, up to 40 Gigabyte nowadays. You can write and delete data on RAM-devices.	2
Explain, using examples if appropriate. interpreter	An interpreter translates (compiles) a high level programming language (a source) into a machine orientated language (machine code). It does this translating line by line (one line stores one line of computer code). By doing so, it will stop as soon as an error is detected. The process is fast, but it will not generate a whole ‘overview’ of the translating. Example: GW-Basic Nowadays compilers are preferred.	3
What is a Barcode?	A barcode is a set of bars / stripes, they can be found as printed labels on articles in a shop. They stand for e.g. an Article number, or an ISBN book number. The barcode contains the unique key-field (e.g. the article number) and the price and description of the article will be looked up in an (attached) database.	2
A hospital uses a computer system to store details about the patients. (a) List three fields that would be in a patient's record, in addition to their name and address. [3] (b) The doctors read the patient medical histories on their computer screens before treating the patients. (i) Describe two checks that should be done by a doctor to make sure that they have the correct patient record on the screen. (ii) State the type of file access that would be used by this system and give a reason why. file access reason why [2] (c) Patient records will need to be amended, deleted and inserted. Give an example of why each of these would need to be done. amended deleted inserted [3] (d) Describe three data protection laws that may apply to patient data. [3] (e) Describe two additional tasks that the hospital computer could do. [2]	a) Birthdate / patient-ID / Insurance company / Gender b) Ask the patient in front of him for his Birthday (and compare to the one on the database screen) b i) Load the picture of the Patient and compare to the person in the room. b ii) random data acces (=direct data access) It allows a fast data lookup, data is stored randomly, the Operating System keeps track of each stored item of data. (study remark: compare acces with serial access = slow) c) amended: when a field of a patient needs to be changed (e.g. their address) deleted: when data is no longer needed (patient moves away, dies :-( inserted: when a new patient comes into the hospital d) Patients may always know about the data stored Patients have the right to (let) change data that appears to be wrong Patients data may only be stored for medical purpose Patients data may not be shared with unauthorized bodies (crosslinking) Patients data may only be stored as long as needed.	10
What is serial access?	It’s a way of reading / writing records one after another (also called sequential). The medium used for this access method is Tape or Cassette. It’s used for long-term storage, as the tape is cheap to use, but data access reading time is high (slow to use). Tape storage is used mainly by banks and insurance companies that need to keep data for a very long time (because of legal reasons, think about bank accounts, life insurance policies)	2
What is Batch processing?	It’s when all input data is collected before hand (and stored in data input files). The processing is done all in one go (a so-called Batch). The output is usually another big file and printed reports (also error listings if something went wrong). Examples are the processing of electricity bills or salary (payroll) slips at the end of a month or year.	2
Put the following in order (it starts with investigate): investigate review / analyse / implement / design	investigate analyse design implement review It’s called the ‘programming life cycle’	2
Why are check-digits used?	It allows to check if input data was entered correctly. A check-digit can be attached to (e.g.) a barcode. If the scanning goes wrong (maybe the label is damaged or dirty) the check-digit check will cause the computer to display an error message (instead of accepting the wrong input data! -> think about the wrong price scanned at a supermarket!)	1
Describe a computer system suitable for a school’s library.	It will consist of Hardware: a networked system (LAN) with several computers. They could be PC’s or Workstations. They will all be connected to the Database file server. a network printer (laser quality) a Barcode scanner (to scan students ID and Book labels) a Receipt printer (for confirmation of borrowed items and paid fees) Software: a Central database system. It can be tailor made or bought ready-from-the-shelve a Backup system (to make regular data backup’s)	3

Some Answers to this years 4F (first year of IGCSE) Information Technology IGCSE exam (International School the Hague)

Some Answers to this years 4F (first year of IGCSE)
Information Technology IGCSE exam (International School the Hague)