Reminder Items

Question 1

What is a program?

Answer 1

A program is a set of instructions written in a programming language that performs a specific task when executed by a computer.

Question 2

What is data?

Answer 2

Data refers to information processed or stored by a computer. It can be in various forms such as text, numbers, images, etc.

Question 3

What does it mean to run the program?

Answer 3

Running a program means executing its code instructions one by one.

Question 4

What computer component executes programs?

Answer 4

The CPU (Central Processing Unit) executes programs.

Question 5

Where is the running program stored? What else (other than the program code) is stored there?

Answer 5

The running program is stored in RAM (Random Access Memory), along with data, variables, and the operating system.

Question 6

What do we know about RAM memory?

Answer 6

RAM is random-access, relatively slow compared to the CPU, and volatile (loses data when power is off).

Question 7

What is memory stall?

Answer 7

A memory stall occurs when the CPU waits for data to be fetched from memory, slowing down processing.

Question 8

What long-term storage do we have?

Answer 8

Long-term storage includes hard drives, SSDs, and other non-volatile storage devices.

Question 9

What is an executable file?

Answer 9

An executable file is a binary file that contains compiled code ready to be executed by the CPU.

Question 10

How do the speeds of CPU, RAM, and hard disk compare?

Answer 10

CPU is the fastest, followed by RAM, and then the hard disk, which is the slowest.

Question 11

What is a machine cycle?

Answer 11

A machine cycle is the basic operation cycle of a computer during which it fetches, decodes, and executes instructions.

Question 12

What are the basic steps of the machine cycle?

Answer 12

The basic steps are: Fetch, Decode, Execute.

Question 13

What does frequency measure? What is the measurement unit of frequency?

Answer 13

Frequency measures how often something occurs per second, measured in Hertz (Hz).

Question 14

What is CPU clock? What is CPU frequency?

Answer 14

The CPU clock synchronizes operations within the CPU. CPU frequency is the speed at which the CPU operates, measured in Hertz.

Question 15

What is CPU core? What does it mean “quad-core CPU,” “octa-core CPU”?

Answer 15

A CPU core is an individual processing unit within the CPU. A quad-core CPU has four cores, and an octa-core CPU has eight cores.

Question 16

How does memory look like?

Answer 16

Memory looks like a linear array of bytes.

Question 17

What is a byte? What is a bit? How many bits are in a byte?

Answer 17

A byte is 8 bits. A bit is the smallest unit of data, representing a 0 or 1.

Question 18

What is a memory address?

Answer 18

A memory address is a unique identifier for a memory location.

Question 19

What is the memory address of a larger chunk of memory?

Answer 19

It’s the address of the first byte of that memory chunk.

Question 20

What is the length of a memory address? What does it mean “32-bit address”?

Answer 20

The length is the number of bits in the address. A 32-bit address can reference 2^32 memory locations.

Question 21

How much memory can we address/use with the given length of a memory address?

Answer 21

With a 32-bit address, we can address up to 4 GB of memory.

Question 22

How long should memory addresses be to address a given amount of memory?

Answer 22

The length should be log⁡2(memory size in bytes)log2​(memory size in bytes). For example, 64-bit addresses for up to 16 exabytes.

Question 23

Can memory contain nothing at all?

Answer 23

No, memory always contains data, even if it’s just zeros or uninitialized data.

Question 24

What is the relationship between a C++ variable, RAM, and a memory address?

Answer 24

A C++ variable is stored in RAM at a specific memory address.

Question 25

What is a C++ pointer?

Answer 25

A pointer is a variable that holds the memory address of another variable.

Question 26

What are the most common sizes of the following C++ data types: char, short, int, long, long long, float, double? Does signed/unsigned affect those sizes?

Answer 26

char: 1 byte, short: 2 bytes, int: 4 bytes, long: 4 or 8 bytes, long long: 8 bytes, float: 4 bytes, double: 8 bytes. Signed/unsigned does not affect sizes.

Question 27

Hexadecimal numbers. Why do we use them? How to convert from hexadecimal to binary and back quickly?

Answer 27

We use hexadecimal for its compact representation of binary data. Conversion is straightforward as each hex digit represents 4 binary bits.

Question 28

What is a “word”?

Answer 28

A word is a fixed-sized unit of data, typically the size the CPU can process in one cycle (commonly 4 or 8 bytes). (I think 8 bytes)

Question 29

What is PC?

Answer 29

The PC (Program Counter) is a CPU register that holds the address of the next instruction to be executed.

Question 30

What is the language that the CPU understands?

Answer 30

The CPU understands machine language (binary code).

Question 31

How can we execute a program written in higher-level languages?

Answer 31

Through a process of compilation or interpretation.

Question 32

What is a compiler? What are compiler advantages?

Answer 32

A compiler translates high-level code into machine code. Advantages include faster execution and optimization of the final program.

Question 33

What is an interpreter? What are interpreter advantages?

Answer 33

An interpreter executes high-level code directly. Advantages include ease of debugging and platform independence.