Stretch tasks Software and Programming Languages

Round 1: Quiz Blitz

1. A web browser Application software serves the user's task.
2. Memory management Without it, one program could crash another.
3. device driver The OS talks to each device through its driver.
4. False Utilities maintain the machine, so they are system software.
5. It gains no speed, and the extra writes shorten its life An SSD reaches every location in the same time.
6. Backup A separate copy lets files be restored.
7. Assembly language Assembly uses mnemonics, roughly one per machine instruction.
8. Translates assembly language into machine code Roughly one instruction at a time.
9. The finished program runs quickly; It can be distributed without the source code Translation is done once, before the program is run.
10. It stops at the first error, making debugging quicker Interpreters win during development. Compilers win at release.
11. False It executes only machine code, so Python must be translated.
12. Device drivers and small embedded systems Where complete control of the hardware matters.

Round 2: Quick Fire

1. • A compiler translates the whole program before it runs, producing an executable
   • An interpreter translates and executes one statement at a time
   Model answer

   A compiler translates the whole program into machine code before it is run, producing an executable file. An interpreter translates and executes the program one statement at a time, every time it is run.

2. • It is close to English, so quicker to write and easier to read
   • It is portable: it runs on any processor with a translator
   • Memory management is handled for you
   Model answer

   High level code is close to English, so it is quicker to write and easier to read and debug. It is also portable: the same program runs on any processor that has a translator, whereas assembly is written for one processor.

3. • It lets the OS communicate with one particular device
   • So applications can use the device without knowing its details
   Model answer

   A device driver is software that lets the operating system communicate with one particular hardware device. Applications can then simply say print this, without knowing anything about the specific printer.

4. • It gathers the parts of each file together
   • So the read head moves less, and files load faster
   Model answer

   Defragmentation rearranges the parts of each file so they are stored together. The read head then moves less to load a file, so files load faster.

Round 3: Big Think

1. • An interpreter reports an error as soon as the line is reached
   • So debugging is quicker
   • But interpreted code is slower, translated on every run
   • And the source code must be given to players
   • For release, compile into an executable
   • Which runs quickly, as translation has already happened
   • And can be distributed without the source code, needing no translator
   • A conclusion, such as interpreting during development and compiling for release
   Model answer

   While the game is being developed, an interpreter is better: it reports an error as soon as the line is reached, so debugging is much quicker. However, interpreted code is slower, because it is translated every time it runs, even each time round a loop, and the source code would have to be given to players. For release, the team should compile the game into an executable, which runs quickly because translation has already happened, can be distributed without the source code, and needs no translator on the player's machine. The executable only runs on the platform it was compiled for, so it must be compiled for each platform. Overall, the team should use an interpreter for development and a compiler for release.

2. • Processor management decides which process gets the processor
   • It switches so fast that they appear to run at once
   • Memory management allocates memory to each program
   • It keeps them out of each other's memory, so none crashes
   • Virtual memory is used if RAM runs out
   • Device management sends the print job through the printer's driver
   • The print job waits in a queue while the user carries on
   • The interface lets the user move between programs
   Model answer

   Processor management decides which process gets the processor and for how long, switching between the browser, the music app and the print job so quickly that they appear to run at the same time. Memory management allocates memory to each program and keeps them out of each other's memory, so one cannot overwrite another and crash it, using virtual memory if RAM runs out. Device management sends the print job to the printer through its device driver, holding it in a queue so the user can carry on. The graphical user interface lets the user switch between the windows.

This or That

1. Software A driver is a program that lets the OS talk to a piece of hardware.
2. Application software It serves the user's task, not the machine.
3. A compiler An interpreter translates one statement at a time as the program runs.
4. Assembly language Machine code is pure binary. Assembly replaces the binary opcodes with mnemonics.
5. No: no gain, extra wear Every location on an SSD is equally fast, and the writes shorten its life.
6. Assembly language A low level language gives complete control of the hardware and memory.
7. Interpreted code An interpreter translates the source every time the program runs.
8. Yes: it is system software Encryption is one of the utilities that maintain and protect the machine.

Memory Match

• A 4 Operating system: Manages processor, memory, devices and users
• B 1 Utility software: Maintenance, such as backup and compression
• C 2 Assembler: Turns mnemonics into machine code
• D 6 Compiler: Translates the whole program before it runs
• E 3 Interpreter: Translates and runs one statement at a time
• F 5 Machine code: Binary the processor executes

Sort It

1. Compiler Only runs on the platform it was built for An executable is tied to one platform.
2. Compiler Reports all errors together at the end Errors come out when compilation finishes.
3. Interpreter Translates again on every run Nothing is kept between runs.
4. Interpreter The same source runs anywhere with the right translator Interpreted code is portable.
5. Compiler Translates the whole program before it runs A compiler translates everything first.
6. Interpreter Slower, especially inside loops Each pass round a loop is translated again.
7. Compiler Can be distributed without the source code Users only need the executable.
8. Compiler The finished program runs quickly Translation has already happened.
9. Interpreter The source code must be given to the user The interpreter needs the source to run it.
10. Interpreter Translates one statement at a time That is how an interpreter works.
11. Interpreter Stops at the first error it reaches Which makes debugging quicker.
12. Compiler Produces an executable file The executable is the compiler's output.