SYS 140 Week 4 Journal - ryanm292002/Ryans-Repository GitHub Wiki

Contiguous Allocation

Basically fixed allocation, basically in this storage method a set limit is given when a file is created, after that limit is created the file cannot exceed that limit. When the file is created a starting length and block is stored.

-Linked list Allocation

In this storage method it can grow dynamically instead of the set limit, but the downfall is that often times there's a missing pointer and it results in missing files.

-Indexed allocation has the ability to grow over time, the user is the one who declares the maximum file size.

-inverted allocation allows for disk blocks to be hashed to file blocks.

Secondary Storage

-Some differences between main storage and secondary storage is that main storage can often be volatile meaning in power mishaps they can be damaged or lose data, while secondary storage doesn't. Main memory is also usually too small to run things like programs permanently. Secondary storage can hold lots of data permanently.

Often times things like access time or disk bandwidth are the factors that make a devices operating system.

Secondary storage often is found in disk form, you can get them in packs of disks when you purchase them. Disks have all different types of characteristics.

When disks allocate space they do it in a system in that the data comes out as blocks. Bigger the block the more fragmentation that results, smaller the block the less the fragmentation but the harder the disk has to work.

When a disk gets an I/O request often an algorithm has to take place to schedule the requests or the performance will get ugly

Storage Devices Overview

Not only can storage be hardware you physically own like a hard drive or a USB, there is also storage devices you can access basically virtually over the internet which is called cloud storage. You don't need to worry about the hardware at all, you just usually buy a plan to use the equipment at a random location.

Hard Drive Overview

Hard Drives are one of the popular type of storage for a device. Hard Drives can come in different sizes as in both length/width and amount of memory.

SSD Overview

SSDs are much more reliable than hard drives because they don't have any moving parts so there's less chance of a failure. SSDs cost way more than hard drives so that's the catch. Another type of hard drive that exists is the hybrid SSD, which has the flash memory of a SSD but the large space of a general mechanical hard drive.

Hard Drive Interfaces Overview

In order for a hard drive to function there needs to be a set of rules running in order for parts to communicate, this system is called the interface. Some popular types of interfaces are PATA, SATA and SAS.

Hard Drive Preparation Overview

Cluster- Smallest amount of space reserved for one file

Sector- What the track is divided into

Cylinder- the track on a hard drive

Fault Tolerance

Basically this can be defined as a situation when hardware or software somehow fails but the fault tolerance system in place allows for that certain thing to keep on working.

  1. Have you used cloud storage in the past? Do you prefer local or cloud storage of your data? Explain your answer. I have used google drive before which is a type of cloud storage, but I prefer local cause I feel like I wont have my data leaked but yet I haven't experienced losing all the data on my failed hard drive yet so who knows.

  2. Do you think adding more platters to a hard drive increases or decreases its mean time between failures (MBTF)? I think in general the more of anything you add to a hard drive the more the chance of a failure will occur.

  3. Based on the storage management handout, do you think contiguous, chained, or indexed allocation is the best method for allocating hard drive space? Linked List Allocation Is the best for allocating space.

  4. Have you encountered RAID in the past? Based on the resilience/performance tradeoffs, which level of RAID do you prefer? Not on any of my personal devices but back in my IT class in high school we had to do a few RAID labs, I wouldn't say I prefer any one over the other.