System Fundamentals Week 4 - CameronProvost/Tech-Journal GitHub Wiki
Storage Methods Handout
Contiguous Allocation
The file's size is determined when it is created and space is made.
Linked-List Allocation
Every block of data is linked to the next piece with a pointer to the next block.
Segment Based Allocation
This uses a segment table to allocate regions of multiple continuous blocks.
Indexed Allocation Indexed allocation uses an index to directly track file block locations.
Multilevel Indexed Allocation
This is used by linux to point out index blocks as opposed to data blocks.
Inverted Allocation
This allocates a disk block by hashing the file block content to a disk block location.
Secondary Storage
Secondary storage is needed because main memory is far too small to store all the information and programs needed. The bulk of secondary storage comes in the form of disks. These disks have allocated blocks which have specific sizes to store different data. This allows the data to be organized and accessed in a quick and efficient manner. Different methods include free space lists, bit maps, linked lists, or free sequence lists. Contiguous allocations allow the files to be stored in contiguous disk blocks. Linked allocation allows the data to be stored randomly and they are linked together through pointers. Indexed allocation creates an indexed list of the location of each file and its pieces.
Storage Devices Overview Storage devices hold all the data we collect and all the data required by the system and programs to run a system. Storage devices come in many different forms which all for different uses. Some are portable and able to be accessed anywhere like USBs, external hard drives, and cloud storage and some like internal storage devices are located inside of a system.
Hard Drive Overview Hard drives are very popular storage devices that can be either mounted internally or connect externally through usb. They come in different form factors and sizes, as well as different storage amounts.
SSD Overview Solid state drives used non volatile flash memory as opposed to hard drive technology. SSDs also eliminate the number one issue for hard drives which is failure due to issues with moving parts. The main drawback to SSDs is the cost which is often much more than a hard disk drive.
Hard Drive Interfaces Overview Each hard drive has specific rules they follow to operate, these rules include the number of heads on a drive which dictate the cables required, the number of bits that can be transferred at one time, and how many devices can be supported. There are several different interfaces, but the most common today is SATA.
Hard Drive Preparation Cluster- is the smallest amount of space reserved for one file and is made up of a specific number of sectors
A Sector- is the smallest amount of storage space on a disk or platter, holding 512 bytes of data
A Cylinder- on a stack of hard drive platters, the same numbered concentric tracks of all platters.
Have you used cloud storage in the past? Do you prefer local or cloud storage of your data? Explain your answer. I have used cloud storage in the past and I prefer local storage of my own data. When it comes to cloud storage most good programs require a subscription, and to assess the data you are required to have an internet connection. So I prefer local storage and when I have to bring data with me I carry a USB drive to store the files I need.
Based on the storage management handout, do you think contiguous, chained, or indexed allocation is the best method for allocating hard drive space? I think Indexed allocation is the best system that makes the most sense to me when it comes to allocation a hard drive. An index for all the data I believe is the best way to keep track of all the files and keep everything organized.