Please answer thème in english

Here are the solutions to the questions from the image:

Question 1:
The question asks which diagram is not used to carry out computations on today's machine architectures, where circles and boxes are data and instruction streams respectively, with input streams to the left. Assuming the standard interpretation where circles represent memory/I/O, boxes represent processing units (CPUs), and lines represent data/instruction flow:

• Diagram A represents a Harvard architecture, which uses separate memory and buses for instructions and data. This is used in many embedded systems and DSPs for performance.
• Diagram C represents a Von Neumann architecture, which uses a single memory and bus for both instructions and data. This is the basis for most general-purpose computers.
• Diagram D is a simplified representation of a single-processor system, essentially a basic Von Neumann model (SISD - Single Instruction, Single Data). This is fundamental and used.
• Diagram B shows two processing units (boxes), each receiving input from both input sources (circles) and sending output to both output destinations (circles). While parallel processing (multiple processors) is common in modern architectures, this specific diagrammatic representation, with each processor fully connected to all input/output sources in this manner, is not a standard fundamental architectural paradigm like Von Neumann or Harvard. It represents a very specific and potentially less common interconnection scheme rather than a general machine architecture. Therefore, it is the most likely candidate for an architecture "not used" in the sense of a fundamental, widely adopted general-purpose model.

The correct option is B.

Question 2:
"Since no machine can start executing without it, it is almost always stored in a"
The initial program that a computer runs when it starts up (e.g., BIOS or UEFI firmware) must be stored in non-volatile memory so it persists when the power is off.

• A. ROM (Read-Only Memory): This is non-volatile memory where the boot-up instructions are permanently stored.
• B. RAM (Random Access Memory): This is volatile memory and loses its data when power is off.
• C. Cache Memory: This is a small, fast, volatile memory used to speed up CPU access to frequently used data.
• D. Swap Memory: This is virtual memory that uses hard disk space as an extension of RAM.

The correct option is A.

Question 3:
"In adding two positive numbers in two's complement arithmetic, the carry bit of the most significant bits (msb) is"
In fixed-width two's complement arithmetic, the carry out of the Most Significant Bit (MSB) is typically discarded for the final result, but it is used in conjunction with the carry-in to the MSB to detect overflow. However, none of the options state "discarded" or "used for overflow detection". If the question implies considering the full mathematical sum that might exceed the fixed bit length, then the carry out of the MSB would become the new, higher-order MSB if the result were stored in an extended number of bits. This is how it works in unsigned arithmetic to get the full result. Given the options, this interpretation makes option A the most plausible.

The correct option is A.

Question 4:
"The Boolean function $X\bar{Y} + XY + \bar{X}Y$ is equivalent to"
Let's simplify the given Boolean expression:

$$F = X\bar{Y} + XY + \bar{X}Y$$

Factor out $X$ from the first two terms:

$$F = X(\bar{Y} + Y) + \bar{X}Y$$

Since $\bar{Y} + Y = 1$:

$$F = X(1) + \bar{X}Y$$ $$F = X + \bar{X}Y$$

Using the absorption law, $A + \bar{A}B = A + B$:

$$F = X + Y$$

The equivalent Boolean function is $\boxed{X + Y}$.