23.2. Compression and Disadvantages

So, whenever we want to optimize based on encoding or compressing of the signals in each of these cells or each of the words in the program control memory, we call it as a vertical micro-program. In horizontal it is very flat and no optimization is there. So now, what way you can do the only way you can do is you have to encode encoded by mean many way xyz.

This chunk introduces the concept of optimization through compression in control memories. It distinguishes between two approaches: vertical micro-programming, which involves encoding to optimize memory usage, and horizontal micro-programming, which lacks encoding and, therefore, optimization.

Imagine packing clothes in a suitcase. Vertical micro-programming is akin to rolling clothes tightly to save space, while horizontal micro-programming is like just folding them without any strategy to save room.

Now, encoding can be very flat like you if there are 16 bits as output, you go for a 4:16 decoder that is the one way of compressing them, there can be several others. So, basically first the most formal or the preliminary way of doing it is basically encode the signals in the control memory.

In this chunk, the focus is on the method of encoding using decoders to compress data. For example, a 4:16 decoder can convert a small input into a larger output, significantly reducing the amount of memory required to store control signals.

Think of a language interpreter translating words into symbols. Just as the interpreter can condense long phrases into short codes while retaining meaning, encoders can reduce the size of control signals while still preserving their functions.

So, instead of 2n the size will just become n or if it is n you will go for log n upper ceiling. So, it is 8 you are going to get 3 highly compressed value we will have, but the problem is that at any point of time only one of these signals can be made 1. So now, the things will start becoming slower.

While vertical encoding optimizes storage, it has a significant limitation. At any given time, only one signal can be activated, leading to potential delays in processing since multiple instructions that would normally execute simultaneously must now be sequenced.

Consider a train station where only one train can depart at a time. Although the schedule (control signals) is efficient, the wait time increases for passengers (signals) wanting to leave.

Say for example generally we know that what happens basically we always have program counter out and memory address register in. So, here what will be happen first you will have to give the value called 001. So, if you are giving the value 001 PC will be equal to 1.

This chunk explains the sequential nature of signal processing in vertical micro-programming. For instance, if the program counter is activated first, it requires a subsequent signal for the memory address, introducing a time delay because they cannot be triggered simultaneously.

Picture a 2-player game where one player must finish their turn before the other can play. The game becomes slower because each player has to wait for the previous one to finish, similar to the time delays in activating signals.

So, here there are 2 disadvantages. One is that you have to you can you will have more number of steps required to give simultaneous 1s to the different control positions. Not only that whatever was one simultaneously required in a horizontal micro-program those values you have to remember like, PC = 1 and MAR = 1 together they should be 1.

The main disadvantages of this approach are the increased number of steps needed to activate multiple signals and the requirement to remember previous activated signals, complicating the micro-program and slowing down operations.

Think of juggling. If you have to catch and throw one ball at a time, it takes longer than if you could handle several balls simultaneously. Managing memory states adds to the complexity, similar to trying to remember where each ball is while only focusing on one.

Now, there is another way as I told there are 2 techniques another way is very interesting that can I make a cluster?

This chunk introduces hybrid methods where clustering is used to address the limitations of vertical micro-programming. By organizing signals into clusters that require fewer simultaneous activations, processing speed can be improved without losing the advantages of compression.

Imagine a team of chefs in a kitchen. Instead of having one person handle all tasks one after the other, they can be grouped into stations (clusters) where they can work on different components of a meal simultaneously, speeding up the cooking process.

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