Question

If a typist types sixty words per minute (where a word is considered five characters), how much time would pass between typing each character? If a multiprogramming operating system allocated time slices in 10 millisecond units and we ignore the time required for process switches, how many time slices could be allocated between characters being typed?

Short answer

It takes 0.2 seconds to type each character, and 20 time slices can be allocated.

Step-by-step solution

Determine Characters Per Minute

A word is considered as five characters. Hence, if the typist types sixty words per minute, we need to multiply the number of words by the number of characters per word to find out the total number of characters per minute. \[\text{Total Characters per Minute} = 60 \times 5 = 300 \text{ characters per minute}\]

Calculate Time per Character

Knowing the typist types 300 characters in one minute, we need to find the time taken to type one character. The time is calculated by taking the reciprocal of characters per minute and converting minutes into seconds. \[\text{Time per Character} = \frac{1 \text{ minute}}{300 \text{ characters}} = \frac{60 \text{ seconds}}{300} = 0.2 \text{ seconds per character}\]

Time per Character in Milliseconds

Convert the time per character from seconds to milliseconds, as the OS allocates time slices in milliseconds. \[0.2 \text{ seconds} = 0.2 \times 1000 \text{ milliseconds} = 200 \text{ milliseconds}\]

Calculate Number of Time Slices

Determine how many 10-millisecond time slices fit into the 200 milliseconds it takes to type one character. This is done by dividing the time per character by the duration of one time slice.\[\text{Number of Time Slices} = \frac{200 \text{ milliseconds}}{10 \text{ milliseconds}} = 20\]

Key concepts

Typist Speed

Typing speed is generally measured in words per minute (WPM), which indicates how many words a typist can type in one minute. In our scenario, the typist's speed is sixty words per minute. This might sound straightforward, but it's essential to note what constitutes a "word" in this context. Here, a word is defined as five characters, including spaces and punctuation.

• This means that a typist who types at 60 WPM achieves a rate of 300 characters per minute (since 60 words × 5 characters per word = 300 characters).
• Understanding typist speed is crucial as this information helps us determine other essential metrics, like the amount of time to type each character.

Keeping track of how fast a typist can work helps in assessing productivity and efficiency, especially in professions requiring extensive typing.

Time Slicing

Time slicing is a fundamental concept in computing that refers to dividing the system's processing time into small chunks, or "slices," which are then allocated to different tasks. Modern multiprogramming operating systems use time slicing to manage multiple processes simultaneously, improving the efficiency of task handling.

• Each time slice affords a process the opportunity to execute for a very short duration, typically measured in milliseconds.
• In our example, the operating system allocates 10-millisecond time slices.
• This setup ensures that even if there are numerous processes waiting, each task gets frequent attention, minimizing wait times and enhancing overall processing speed.

Understanding time slicing is essential for grasping how computers juggle multiple applications and services effectively.

Multiprogramming Operating Systems

Multiprogramming operating systems are designed to run several programs simultaneously by sharing resources. They utilize techniques like time slicing to execute multiple processes, switching between them so quickly that it seems they are running concurrently.

• The main goal is to optimize CPU usage, minimizing idle time and ensuring tasks progress smoothly.
• In a multiprogramming environment, the operating system might allocate time slices to these tasks according to specific needs, potentially prioritizing more urgent processes.
• This kind of efficient resource management allows users to run multiple applications without significant delay, enhancing the computing experience.

Appreciating how multiprogramming systems manage tasks can provide deeper insights into how modern computers maximize efficiency.

Character Typing Time

Character typing time is the interval required for a typist to input one character. It is essentially determined by dividing the typist's total character count per minute by sixty seconds.

• In our example, it takes 0.2 seconds to type a single character, given a typing speed of 300 characters per minute.
• Converting this time into milliseconds, we find it takes 200 milliseconds per character.
• This calculation is fundamental for understanding how much CPU time may be needed or available between keystrokes in computational processes.

Knowing the exact delay between characters is valuable for improving typing techniques or planning CPU resource allocation in computer systems.