18. 8. Retell the dialog in indirect speech. Text 2. Supermarket checkout

1. Discuss the following questions in pairs:

1. How do you use computers in your free time?

2. What other areas of study would benefit from the introduction of computers?

3. Make a list of as many users of the computer as you can think of.

4. How do you think these professions might use computers? (musicians, sales people, teachers, artists)

2. A) Match the verbs with the prepositions to make collocations:

1. used a) out

2. go b) from

3. move c) out

4. consist d) over

5. find e) to

6. come f) of

7. work g) in

B) Use the collocations from A) to complete the sentences:

1. Computers are widely ___________ the supermarket checkout system.

2. An assistant __________ the product ________a window.

3. A barcode reader _____________ a light source, a lens and a light sensor.

4. The computer can ___________ stock levels.

5. He ____________ that the president of a local food chain wanted to find an automatically read product information system.

6. The idea __________ Morse code.

7. The numbers _________ the computer.

3. Read the text and give the main idea of each paragraph:

Nowadays computer power is widely used in the supermarket checkout system which is a sophisticated input unit to the store's computer. Each product has a bar code that contains an identification number. The assistant moves the product over a window and an invisible infra-red laser beam scans the bar code, reading it at any angle. The number goes to the computer, which instantly shows the price of the product on the checkout display. The computer also adds up the check.

A barcode is a series of parallel bars or lines of varying width that is used for entering data into a computer system. The bars are typically black on a white background, and their width and quantity vary according to application. The bars are used to represent the binary digits 0 and 1, a wide bar or space signifies 1 and a thin bar or space signifies 0. Sequences of these binary digits can represent numbers from 0 to 9 and be processed by a digital computer. There are several different kinds of bar codes but in each one, a number, letter or other character is formed by a certain number of bars and spaces. Barcodes can be read by optical scanners called barcode readers, or scanned from an image by special software.

A barcode reader consists of a light source, a lens and a light sensor translating optical impulses into electrical ones. Additionally, nearly all barcode readers contain decoder circuits which analyze the barcode's image data and send the barcode's content to the scanner's output port. There are six basic kinds of barcode readers: a handheld scanner, a pen scanner (or a wand scanner), a stationary scanner (commonly found at the checkout counters of supermarkets), a fixed position scanner (often used to identify products during manufacture or logistics), a PDA scanner and an automatic reader (used in offices to read barcoded documents at high speed).

The idea of a barcode appeared early in the 20^th century when Bernard Silver, a graduate student at Drexel Institute of Technology in Philadelphia, USA found out that the president of a local food chain wanted to find a system which would automatically read product information during checkout. Silver together with his friend Norman Woodland started working on a variety of systems. The inspiration came from Morse code, and the researches patented their invention in 1949. At first, barcodes were used to label railroad cars, but they were not commercially successful. Then they began to be used to automate supermarket checkout systems, a task in which they have become almost universal.

Checkout computers give the customer rapid accurate service, and they also benefit the store. The computer keeps a complete record of purchases and can work out stock levels. When the stock of a particular product falls, the computer can automatically order a new supply. The computer can also tell the store which products are selling well and which are less popular.