1. Storage and File Organization Flashcards
Volatile storage: ___
Example: ___
Loses contents when power is switched off
RAM
Non-Volatile storage: ___
Example: ___
Contents persist even when power is switched off
ROM (HDD)
Storage Hierarchy (6 levels)
Cache Main Memory (RAM) Flash Memory (flash drive and SSD) Magnetic Memory (HDD) Optical Disk (CDs or DVDs) Magnetic Tapes
On an HDD each surface of a ___ is divided into ___ that are divided into ___
Platter
Tracks
Sectors
On an HDD a sector is the smallest unit of ___ that can be ___
Data
Read or written
On an HDD a disk controller represents the ___ between the ___ and the ___
Interfaces
Computer System
Disk Drive Hardware
Access time is the time it takes ___
From when a read or write request is issued to when data transfer begins
Seek time is the time it takes to ___
Reposition the arm over the correct track
Rotational latency is the time it takes for ___
The sector to be accessed to appear under the head
Data-transfer rate is the rate at which ___
Data can be retrieved from or stored to the disk
Disk block is a ___
A logical unit for storage allocation and retrieval0
Sequential access pattern represents:
1- Successive Requests are for ____
2- Disk seek required for ___
1- Successive disk block
2- First block only
Sequential access pattern represents:
1- Successive Requests are for ____
2- Disk seek required for ___
Transfer rates are low since a lot of time is wasted in ___
1- Blocks that can be anywhere on the disk
2- Each access
# Seeks
I/O operations per second (IOPS) represents the ___
Number of random block reads that a disk can support per second
Mean time to failure (MTTF) represents the average time the ___
Disk is expected to run continuously without any failure
Disk is expected to run continuously without any failure
Disk organization techniques that manage a large numbers of disks
RAID provide a view of a single disk of:
1- High ___ and high ____ by using multiple disks in ____
2- High ___ by storing data ___, so that data can be recovered if a disk ____
1- Capacity / Speed / Parallel
2- Reliability / Redundantly / Fails
Mirroring is the process of ___
Duplicating every disk
Block-level striping relies on ___
Writing consecutive blocks on different disks, in the hopes of running requests in parallel in the future
RAID 0: ___
RAID 1: ___
RAID 5: ___
RAID 6: ___
0 - Block Stripping
1 - Morrored Disks
5 - Block-Interleaved Distributed Parity
6 - Equal to 5 but stores two error correction blocks (P,Q) instead of a single parity block
When to choose each level of RAID? 0 - \_\_\_ 1 - \_\_\_ 5 - \_\_\_ 6 - \_\_\_
0 - Data safety is not important
1 - Better write perfomance than 5 but higher storage cost
5 - For applications where writes are sequential and large, and need high storage
6 - Data safety is very important
File organization in a ___ manner bennefits ___
Sequential
Disk block access
HDD speeds benefit from ___
Sequential Data
In terms of seek time, SSDs ___
do not have it
RAID means ___
redundant arrays of independent disks
RAID can help improve:
- Reliability via ___
- Performance via ___
. Redundancy (several copies)
. Parallelism
RAID level 0 refers to disk arrays with striping at the ____
but without any ___
. level of blocks
. redundancy
RAID level 1 refers to disk ____ with block stripping
mirroring
RAID level 5 refers to ___
block-interleaved distributed parity
Types of hardware failures:
- Latent ___
- Data ____
- Hot ___
Failures
Scrubbing
Swapping
Techniques to Optimize Disk-Block Acess:
- B___
- R___
- D___
- F___
Buffering
Read-ahead
Disk-arm-scheduling
File organization
Fixed-Length Records represent records with ___, while Variable-Length Records arise in the form of ___, record types that allow ___ and record types that allow ___
Fixed size
Multiple records
Variable length (like strings)
Repeating fields
Heap file Organization places records ___
Anywhere in the file system where there is free space
Sequential File Organization places records ___
in a sequential order according to a search-key
In Table partitioning, records in a relation can be ___ that are ___
Partitioned into smaller relations
Stored separately
Data dictionary stores metadata such as:
- Information about ___
- ___ and accounting information
- ___ and descriptive data
- Physical file ___ information
- Information about ___
Relations User Statistical Organization Indices
The buffer manager is responsible for giving ___ from ___ to ___
Blocks
Disk
Programs
Column-Oriented Storage store each attribute of a relation ___
Separately
