No_5_May_1968 — Page 41

TH

by R. A. Callow and A.A. Bunting

"HE work of maintaining a realistic check on costing throughout a project can be very time consuming for the architect, the quantity surveyor and the engineer, since many factors may be influenced by the variation of any one other factor.

If full and accurate cost control is to be achieved and anything less than than this renders the exercise useless all permutations must be done and these may be beyond the physical capabilities of the building

team.

―

They involve not complex calcula- tions but a multitude of relatively elementary, repetitive problems. Here the digital computer comes into its own. It does not need to rest, as the human brain must.

Two types of computer are in common service the analogue computer, which works by the use of physical similarity in its computation, and the digital computer which uses a system of high-rapidity counting of digits and delivers the results in this form.

Both are large, highly expensive, complex machines and in recent years manufacturers have turned their re- search to the production of a smaller, cheaper and simpler unit which would appeal to a wider market. One result is the desk-top digital computer a machine which the successful architect can afford and his staff can operate.

In testing one of these machines to examine its potential for use in architectural cost planning, the authors used, because of its availabili- ty, an Olivetti Programme 101. This has the computer characteristics of:

a. accepting and recording pro-

grammes;

b. storing programmes;

C.

making logical decisions. Briefly, it has an "immediate memory" (Register 'M') which can receive digits; and an "executive lobe" (Register 'A') into which mathematical instructions may be fed together with

Far East BUILDER, May 1968.

*

orders to transfer to other portions of the system (here logical decisions are carried out). It also has ten "memory-storage" lobes (Registers (b) B, B, (c) C/, C, (d) D/, D, (e) E/, E, (f) F/, F), each of which can store eleven digits plus the decimal point.

If all ten of these latter registers are in full use, 48 instructions may be given in one programme. If, how- ever, more instructions are necessary (up to a maximum of 120 instruc- tions) six of the ten storage registers (Registers (d) D. D. (e) E/. E, (f) F/, and F) may be used, with a con- sequent reduction in the capacity for "memory-storage".

The first advantage which became apparent was the use of normal "Romanised" letters and digits (plus certain simple symbols) instead of the punch-tape which adds to the mystery of larger computers.

Usability

To form a criterion of the small computer's usability within the archi- tectural profession, all programming was done by Callow (who, as a former classicist, has little aptitude for mathematics), while Bunting acted as "control" by manually undertaking the work in traditional quantity sur- veying manner.

was

A series of three buildings of similar construction 19 in. brickwork bedded in 1:3 cement/sand mortar, 6 in, concrete (1:2:4 mix with a water/- cement ratio of 0.57) subfloor on 9 in. of consolidated hardcore] selected, each building having a dif- These ferent shape (as at figure 1). three shapes were subdivided, as in standard quantity surveying practice, into five rectangles.

The programme at figure 2 was written in the space of one hour by the architect. It was then recorded

by the computer by feeding in the programme symbols in succession on the keyboard. (This process could be

carried out by a typist.) The machine then had retained the programme in its memories.

For permanent storage a two-sided magnetic-storage card was passed through the computer and the pro- gramme recorded upon it. while also being retained in the com- puter's memories. The magnetic card may be repassed through the ma- chine at any subsequent date at which time the computer will read the stored programme, retain its content in its memory and act upon this when or- dered to do so. By these means, pro- gramme-storage becomes a matter of routine filing and programmes may be re-used at will.

The relevant magnetic card was fed into the computer by a typist who then activated the programme com- putation by depressing a code key. The quantity surveyor had pre- viously measured off the dimensions of each rectangular area and provid- ed the variables (S) to the typist in the following form:-

S1

=

S

S

S =

50.00 ft. (dimension of side Area No. 1)

of

20.00 ft. (dimension of side of

Area No. 1)

0.75 ft. (depth of hard core)

0.50 ft. (depth of concrete)

The typist fed into the computer's key board these four sets of digits with their decimal points and the computation took place. (The gra- phical form of this and written sequences are set out at figures 2 and 3). The machine automatically printed out the contents of its stored computed memories.

By referring to the "Contents of Registers" column on the programme and the printed digital results, the typist then typed:---

Area of hardcore Volume Weight Area of concrete Volume

1,000.00 f.s.

27.77 y.c. 34.71 tons

51

12

**

"

1,000.00 f.s.

17

18.51 y.c.

* R.A. Callow, PIS, Dip. Arch, FRIBA, APAM, and A. A. Bunting, ARICS, DPA, AALPA, are lecturers with the Depart- ment of Architecture, University of Hong Kong.

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