31.3.2. Finding a Sector

Secondly disk rotate in a constant angular velocity. Now you just see since it is rotating a constant angular velocity, so the time required to cover this particular length will be equal to time required to traverse this particular length, because it is rotating in a constant angular velocity.

This chunk explains that a disk rotates at a constant angular velocity, meaning that the speed of rotation does not change. Because of this constant rotation, the time it takes to reach any specific location on the disk remains consistent, regardless of whether that location is on the inner or outer tracks of the disk.

Think of it like a merry-go-round at a playground. If it spins at a constant speed, the time it takes for a child sitting on the edge to reach a certain point is the same as for a child sitting closer to the center. Both will reach their points in the same amount of time since the merry-go-round rotates uniformly.

So, time required to retrieve the information from a particular sector is same whether it is an inner track or an outer track, ok, so it works on constant angular velocity.

This segment points out that because the disk operates at a constant angular speed, the time to access information is consistent across different tracks. Therefore, whether you are retrieving data from the inner track or the outer track, the time taken remains the same, simplifying the retrieval process.

Imagine you are on a roundabout. No matter whether you are closer to the center or further out, once the roundabout spins steadily, it takes the same time to reach any point. Similarly, the disk's tracks provide a uniform access time.

So, this is basically known as my block of the disks, so we are going to work with the block of a disk. Straightaway I cannot identify this particular position and I go to that point I can very well come to the start of this particular sector and from that I am going to access the information.

In this part, it's discussed that data is organized into blocks within the disk. When trying to access data, it is not possible to jump straight to a specific bit; instead, you first identify the sector, or starting point of a block, and then access the information sequentially from there.

Think of a library. You can't simply dive into the middle of a book. First, you must find the book on the shelf (the start of the sector) and then read through the pages to find the information you need (accessing the block).

Now for that we have to give the address. Now what is the addressing format? You just see that we are having the format like that it is talking about that sector number, surface number, and track number.

This chunk describes how to specify where data is located on the disk using an addressing format which consists of three components: sector number, surface number, and track number. This structured way of addressing helps in precisely locating the data needed to be accessed.

Imagine mailing a letter. The address on an envelope is essential for it to reach the right location. Similarly, the sector, surface, and track numbers serve as a precise location guide for locating specific data on a disk.

Now, generally we are having some idea about the file we say that we are storing some file in hard disks and we generally access those particular files.

This paragraph talks about how files are stored on a disk and accessed later. Each file occupies certain sectors, and it's noted that there might be some unused space represented as 'wastage' when new files are written. The management of this space is crucial to efficient disk use.

Think of your computer’s storage as a filing cabinet. Each file (like a folder) occupies space in the cabinet. If you don’t organize it properly, you could end up with empty drawers that are hard to see or reach, just like wasted space on a disk.

So, this is the way you can calculate what is the capacity of a hard disk.

This chunk points towards understanding how to determine the total capacity of a hard disk by using its component structure, like how many sectors are present in each track and across how many surfaces. Each factor influences the total storage capacity.

Imagine measuring the volume of a box. You need to know the dimensions: length, width, and height. Similarly, to assess a hard disk's capacity, you must look at its size in terms of sectors, tracks, and surfaces.

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