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4.2  What do the terms static and dynamic allocation of memory mean?

4.4  We use the terms ROM to identify read only memory and RAM to designate random access memory.  What is the major difference between the two kinds of memory?

4.5  Does ROM memory support random access?

4.6  What so the terms SRAM and DRAM mean, and what are the major differences between the two types of RAM?

4.7  What are the major difference between the following types of read only memory: ROM, PROM, EPROM, EEPROM, and FLASH?

4.8  What are the major interface signals in a basic memory system? What is the purpose of each?

4.19  What is a memory map?

4.21  What kinds of information are typically identified in a memory map?

4.32  What is an associative search?

4.35  Explain the terms block-set associative and two-way set associative with respect to cache memory management.

4.39  Describe how the overlay scheme works to support programs larger than will fit in main memory.

Chapter 5:

5.1  Why do we use UML and structured design methodologies when developing embedded systems?

5.2  What information does a static view of an embedded system provide? A Dynamic view?

5.4  Explain the terms thread and thread of control.

5.7  Where did UML originate, and why was it developed?

5.10  What is the purpose of UML diagrams?

5.11  What are the major classes of UML diagrams or drawings? Five a one or two sentence description of the purpose of each type of drawing.

5.13  What does a use case diagram provide for us?

5.28  What information does a dynamic model give us about a design?

5.29  What are the major elements that should be included in a dynamic model?

5.36  For what purpose do we use an activity diagram?

Explanation / Answer

1.

Static memory allocation: The compiler allocates the required memory space for a declared variable.By using the address of operator,the reserved address is obtained and this address may be assigned to a pointer variable.Since most of the declared variable have static memory,this way of assigning pointer value to a pointer variable is known as static memory allocation. memory is assigned during compilation time.

Dynamic memory allocation: It uses functions such as malloc( ) or calloc( ) to get memory dynamically.If these functions are used to get memory dynamically and the values returned by these functions are assingned to pointer variables, such assignments are known as dynamic memory allocation.memory is assined during run time.

2.

There is one major difference between a ROM chip and a RAM chip.

A ROM chip does not require a constant source of power to retain the information stored on it, whereas a RAM chip does require a constant source of power to retain the information. When a computer is turned on, and programs are being run, the programs information is stored in the RAM chip for better efficiency and speed. However, as soon as the computer is turned off any information stored in the RAM chip is lost. With a ROM chip, any information stored on the chip remains on it with or without power.

ROM chips are commonly used in gaming system cartridges, like the original Nintendo, Gameboy, Sega Genesis, and a number of others. The game cartridge stores the game programming on a ROM chip which is read by the game console when the cartridge is inserted into the console.

ROM chips can also be found in computers, to store the programming needed to begin the initial boot up process when turning on a computer. Using non-volatilestorage is the only way to begin the start up process for computers and other devices that use similar a start up process. The most common type of programmable ROM (PROM) chip in a computer is the BIOS.

RAM chips are also used in computers, as well as other devices, to store information of the programs currently running on the computer. However, only volatileinformation can be stored on RAM chips, due to that fact that if power is lost to the computer all information stored in the RAM is lost.

3. YES

4.Short for static random access memory, and pronounced ess-ram. SRAM is a type of memory that is faster and more reliable than the more common DRAM(dynamic RAM). The term static is derived from the fact that it doesn't need to be refreshed like dynamic RAM.

While DRAM supports access times of about 60 nanoseconds, SRAM can give access times as low as 10 nanoseconds. In addition, its cycle time is much shorter than that of DRAM because it does not need to pause betweenaccesses. Unfortunately, it is also much more expensive to produce than DRAM. Due to its high cost, SRAM is often used only as a memory cache.

There are two types of Random Access Memory or RAM, each has its own advantages and disadvantages compared to the other. SRAM (Static RAM) and DRAM (Dynamic RAM) holds data but in a different ways. DRAM requires the data to be refreshed periodically in order to retain the data. SRAM does not need to be refreshed as the transistors inside would continue to hold the data as long as the power supply is not cut off. This behavior leads to a few advantages, not the least of which is the much faster speed that data can be written and read.

The additional circuitry and timing needed to introduce the refresh creates some complications that makes DRAM memory slower and less desirable than SRAM. One complication is the much higher power used by DRAM memory, this difference is very significant in battery powered devices. SRAM modules are also much simpler compared to DRAM, which makes it easier for most people to create an interface to access the memory. This makes it easier to work with for hobbyists and even for prototyping.

Structurally, SRAM needs a lot more transistors in order to store a certain amount of memory. A DRAM module only needs a transistor and a capacitor for every bit of data where SRAM needs 6 transistors. Because the number of transistors in a memory module determine its capacity, a DRAM module can have almost 6 times more capacity with a similar transistor count to an SRAM module. This ultimately boils down to price, which is what most buyers are really concerned with.

Because of its lower price, DRAM has become the mainstream in computer main memory despite being slower and more power hungry compared to SRAM. SRAM memory is still used in a lot of devices where speed is more crucial than capacity. The most prominent use of SRAM is in the cache memory of processors where speed is very essential, and the low power consumption translates to less heat that needs to be dissipated. Even hard drives, optical drives, and other devices that needs cache memory or buffers use SRAM modules.

5.

ROM: Read Only Memory

ROM is only programmable once. For example, it could be programmed at the factory where they make the chip. And indeed, it

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