• Practicals

  5.1 Writing practical reports

  5.2 Late practicals

  5.3 Practical marks

Practicals

Practical classes for courses organised by the Computing Laboratory take place in the Practicals Laboratory on level six of the Thom Building, where demonstrators will be present to assist you in overcoming any difficulties you may experience. Attendance at these practical classes is compulsory, according to the rules explained below, if you are to get full credit for practical work in the examinations. The purpose of practical exercises for the Computer Science courses is to help you make sure you understand the application to practical programming of the theory that is taught in lectures; demonstrators at the practical classes are there to help you learn as much as possible from them.

For each lecture course with a practical component, a series of supervised practical classes will be arranged. For example, a course with two practical exercises might have a practical timetable as follows:

Weeks 2, 3, 4, 5 Classes for first practical

Weeks 6, 7, 8 Classes for second practical

A similar pattern will be followed for each lecture course, except for lecture courses in Trinity Term which will have the final class in week 4, and practical reports will be due on Friday of week 4 of Trinity Term.

Practicals are assessed in two ways: first, the demonstrators keep a record of who has attended the practical classes and completed each practical exercise associated with a lecture course; and second, you write a practical report that the demonstrators mark, and which you submit to the examiners before you sit the written exam.

If you are taking a lecture course with practicals, you must sign up for the practical class within the first two weeks of term, using the sign-up sheets that are posted in the Practicals Laboratory. When you attend a practical class, you will find that specific machines have been reserved for the practical, and there will be a register for you to record your presence. You are expected to attend the classes for each practical until you have completed it.

For example, with the timetable shown above, you must begin attending practical classes for the course in week 2. If you complete the first practical early, say in week 4, then you may attend the class in week 5 in order to start the second practical, but you are not obliged to do so. Unless you have already finished both practicals, you will be expected to attend again in weeks 6, 7 and 8. If you are unable to attend a practical, for example because of illness, you should inform the demonstrator in charge.

These rules are made with three purposes in mind: to make it easy for you to avoid getting behind with your practical work; to make it easy for the demonstrators, who can mostly concentrate on demonstrating the practical that is currently active; and to enable the examiners to be sure that work signed off by the demonstrators is your own.

In order to have the demonstrator record that you have completed the practical, you must show them that you have done the work, perhaps by demonstrating a working program. In the ordinary way of things, you will have done the work in the lab with the demonstrator's help, and he or she will be able to check quickly that you have finished. You may prepare your practical work in advance of a practical class and bring it for checking at the class, but the demonstrators will not check off your work unless you have been attending the practical classes.

You are encouraged to write up reports on practicals as you do them during the term. The demonstrators will happily look at your reports and give you advice about them at the practical sessions, and will mark them there and then. It is perfectly acceptable to have your report marked at one practical session, then do further work on the practical and submit an improved report by the deadline. Please note that you must turn up at the beginning of the session in which you wish your practical to be marked; the demonstrators will not have time and will not be willing to mark your practical if you turn up for only the latter part of the session.

All the practical reports must be submitted to the examiners at the end of the year, using the procedure set out in the Grey Book. You must submit them to the Examiners, via the Academic Administrator in the Computing Laboratory, by noon on Monday of Week 5 of Trinity Term; full details will be given nearer to that date. Note that reports should be anonymous: they should contain your candidate number, but not your name.

You must do the practicals for each course in the year you offer it for examination. You may not do some of the practicals for a particular lecture course in one year and some in another year.

5.1 Writing practical reports

Each practical requires a report to be submitted for assessment. The report should not be a major burden: it is simply to provide evidence that you have done the work properly. Practicals should contain specific instructions as to what should be included in the practical report. In any case the following guidelines should be followed.

In many practicals, most of the report will be in the form of a program. Of course, you are expected to follow good programming practice:

• in a multi-module program, you should include some text explaining the role of each module, and the relationship between them;

• you should include suitable comments explaining the purpose of variables and procedures;

• you should also include comments to explain any interesting algorithms you have used: writing down an invariant will often help;

• you should make the code easy to read, for example by following standard indentation conventions, and by suitable use of white space;

• you should also include some evidence that the program works, for example by including sample output or screen shots: testing is a very important programming skill, and so you should show that you have considered suitable tests.

If the aim of the practical is to produce some experimental results, then you should present and discuss those. Do not just include pages and pages of numbers spewed out by the program. A concise summary is better, perhaps using another program to show the results are correct (by making a graph, say).

Try to avoid reproducing large volumes of code from the practical materials or repeating program code that you have already listed in the report. If a second program has to include the same procedure definition (say), just write "Procedure Sort(x) defined as before."

You may want to use text formatters like TeX or LaTeX to produce reports, or word processors running on your personal computer. Be careful that the time you spend in formatting the document prettily does not distract you from getting the content right. A cogent, concise, neatly hand-written report is preferred to pages of word-processed verbiage. If you do produce a typed report, please ensure that it is legible, with adequate margins and with type that is no smaller than 10 points. While working on your practical, keep a record of the tests you performed on your program, so that you can easily copy relevant data into your report.

Do not copy any other person's practical report: if you do, you are likely to end up in trouble with the Proctors. You may have general discussions with other students about the practicals, but the report must be all your own work.

5.2 Late practicals

Practicals are intended to support the lectures and tutorial work on a course, to help to impress material on your understanding, and to connect theory with practice. Accordingly, it is very much better to be doing the practicals for a lecture course at the same time as the other work on that course. Deadlines are set to help you to resist the temptation of putting off practicals.

Another advantage of doing your practicals during the scheduled classes is that the demonstrators are often able to spot problems that are affecting several people and do something about them, perhaps clarifying the instructions or providing a piece of missing information. If you do not attend the practical classes, you will not have access to this help.

Under the rules specified in the Examination Regulations, the Examiners will not take into account practical reports unless they have been "signed by a demonstrator". The markers will sign the reports when they mark them.

The Examiners will give you no credit for practical work that was not submitted for marking by the deadline and signed by a demonstrator, unless there are extenuating circumstances. Likewise, the demonstrators will not mark work that is late, unless there are extenuating circumstances. If there is a good reason why you can't submit your practical on time, for example because you were ill, then you may submit your practical late through your tutor.

5.3 Practical marks

When you have completed the work for a practical and the report on it, a demonstrator will check and mark your work at a practical session. The demonstrator will ask you first to show that you have done the work, leaving aside any optional parts, and will record this fact in their register, together with your attendance at practical sessions. If a practical turns out to be very long or difficult, the demonstrators (with the advice of the course lecturer) may record the practical as complete if you have done a reasonable amount of work, even if you have not finished it.

The demonstrator will also mark your report, either at the practical session if there is time, or by taking it away and returning it later. The practical report will be marked, taking into account whether you have done any optional parts, as well as the quality of your write-up, and the general difficulty of the practical exercises. As a general guide, even an incomplete report on each practical in the course gains more credit than one where some practicals are entirely missing. Extra credit is awarded for completing optional parts of practicals, but not to such an extent that it is worth spending many hours finishing every optional part.

The following scale of marks is used by the markers; the descriptions attached to each mark indicate the rough level of performance expected, but may be adjusted to take into account the degree of difficulty of the practical exercise.

S+ The student has either completed the compulsory parts of the exercise and submitted an exemplary report, or completed all parts of the exercise and submitted an adequate report.

S The student has completed the compulsory parts of the exercise and submitted an adequate report.

S- The student has completed only part of the exercise, or has submitted an inferior report.

In examinations, the marks for practicals are treated separately from those for written papers. Practical marks do not affect the class of degree that you will be awarded, but it is necessary to achieve a pass mark in practicals in order to pass the exams.