CS401A's Finals: Comp. Sys. Architect Module 07 Flashcards
For final exams. (94 cards)
1
Q
Computer Storage
are computer hardware used to remember or store data.
A
Storage devices
2
Q
Computer Storage
These devices can be divided into \_\_\_\_\_ (_) types based on the access to stored data and access to devices:
A
two (2)
* Serial access
* Random access (direct)
3
Q
Computer Storage
— This means that when reading a data item, all previous items have to be read or skipped.
A
- Serial access
4
Q
Computer Storage
The major limitation of \_\_\_\_\_\_ \_\_\_\_\_\_ storage devices is that the location of the searched item influences the search time.
A
-
Serial access
serial access storage devices
5
Q
Computer Storage
— It is possible to get to the required item directly.
Memory, for example, is a direct-access device.
A
- Random access (direct)
6
Q
Computer Storage
The access time for obtaining a data item using \_\_\_\_\_\_ \_\_\_\_\_\_ storage devices is almost similar for all items, regardless of their location.
A
-
Random access (direct)
direct access storage devices
7
Q
Computer Storage
Hierarchy of Storage
A
- Primary Storage
- Secondary Storage
8
Q
Computer Storage
— The CPU accesses the data or instruction in the conventional memory (RAM) if the data in the cache memory is not present.
A
- Primary Storage
9
Q
Computer Storage
Both conventional and cache memory provide immediate access to program instructions and data by the CPU and can be used for the execution of programs.
A
- Primary Storage
10
Q
Computer Storage
— This is the level of conventional memory in which the storage in the hierarchy is not immediately available to the CPU.
A
- Secondary Storage
11
Q
Computer Storage
This is treated as the I/O where data and programs must be copied to primary memory for CPU access.
A
- Secondary Storage
12
Q
Computer Storage
Except for flash memory, access to \_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_ is significantly slower than \_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_.
A
-
Secondary Storage
secondary storage
primary storage
13
Q
Computer Storage
Kinds of Storage
A
- Magnetic Disks
- Solid State Memory
- Optical Disks
- Magnetic Tapes
14
Q
Computer Storage
— These consist of one (1) or more flat, circular platters made of glass, metal, or plastic, and are coated with a magnetic substance.
A
- Magnetic Disks
15
Q
Computer Storage
Particles within a small area of the magnetic substance can be polarized magnetically in one of the two (2) directions with an electromagnet.
A
- Magnetic Disks
16
Q
Computer Storage
An electromagnet can also detect the direction of polarization previously recorded. Thus, magnetic polarization can be used to distinguish 1’s and 0’s.
A
- Magnetic Disks
17
Q
Computer Storage
A drive motor rotates the disk platter(s) on its central axis. On most drives, the motor rotates the disk at a fixed speed. An arm has the read/write head mounted at the end, where each arm contains two (2) read/write heads that services the surfaces of two (2) adjoining platters.
A
- Magnetic Disks
18
Q
Computer Storage
○ With the head in a particular position, it traces out a circle on the disk surface as the disk rotates; this circle is known as a \_\_\_\_\_.
○ Since the heads on each surface all line up, the set of tracks for all the surfaces form a \_\_\_\_\_\_\_\_.
○ Each track contains one (1) or more blocks of data. Traditionally, the surface of the disk platter are viewed as divided into equally sized pie shape segments, known as \_\_\_\_\_\_\_, although current disks divide up the track somewhat differently.
○ Each sector on a single track contains one (1) \_\_\_\_\_ of data, typically 512 or 4,096 bytes, which represents the smallest unit that can be independently read or written.
A
-
Magnetic Disks
track
cylinder
sectors
block
19
Q
Computer Storage
Disk Characteristics
A
○ Access Time
○ Reading or writing time
○ Seek Time
○ Rotational Delay
○ Rotation speed
○ File system
20
Q
Computer Storage
— This refers to the time that takes to start transfer data. It is also the sum of seek time and rotational delay.
A
○ Access Time
21
Q
Computer Storage
— This refers to the time required for the head to read or write the data.
A
○ Reading or writing time
22
Q
Computer Storage
depends on the electronic data transfer
(the head is over the requested location, and all it has to do is read or write the data).
A
○ Reading or writing time
The reading or writing time
23
Q
Computer Storage
— This refers to the time that takes the head move to the proper track.
A
○ Seek Time
24
Q
Computer Storage
— This refers the time that it takes a sector to be positioned under read/write head, depending on rotation speed.
A
○ Rotational Delay
25
# **Computer Storage**
— This is represented by revolutions per minute (RPM) and assums that the sectore is away from head half of the track;
○ **Rotation speed**
26
# **Computer Storage**
therefore, the Disk File System calculates the `________ _____`.
○ **Rotation speed**
rotation delay
27
# **Computer Storage**
— This defines the organization of information stored in the hard disk.
○ **File system**
28
# **Computer Storage**
○ **File system**
Here are the common file systems of OS:
◼ Linux — EXT, XFS
◼ Windows — FAT, NTFS
◼ Mac OSX — HFS+, APFS
29
# **Computer Storage**
— It is a solid state storage medium that uses volatile memory as a means of holding and accessing data.
* **Solid State Memory**
30
# **Computer Storage**
is based on NAND Flash chips which differs from RAM in terms of usage and volatility.
* **Solid State Memory**
Solid state memory
31
# **Computer Storage**
is well suited for secondary storage in many cases. Because of its small size, low power consumption, and light weight, it is frequently the secondary storage of choice, which is used for both long-term system storage and portable storage.
* **Solid State Memory**
Flash memory
32
# **Computer Storage**
The ability to access stored data quickly is a limiting factor in the execution speed of many important computer applications.
* **Solid State Memory**
33
# **Computer Storage**
The new technological developments regarding `___` pushed its small size and usage at an increasing pace.
## Footnote
For example, NVMe `____` have higher and faster data reads/writes.
* **Solid State Memory**
SSD
SSDs
34
# **Computer Storage**
— These are an alternative to magnetic disk storage.
* **Optical Disks**
35
# **Computer Storage**
These include various types of CDs and DVDs, in read-only, write-once, and read/write forms.
## Footnote
For example, an inexpensive CD-ROM, 12 centimeters in diameter, stores approximately 650 MB, while a Blu-ray DVD of the same physical size can hold more than 50GB of data.
* **Optical Disks**
36
# **Computer Storage**
is essentially similar to CD-ROM technology in terms of size and format.
* **Optical Disks**
* DVD technology
37
# **Computer Storage**
The only difference is the use of a laser with a shorter light wavelength which allows tighter packing of the disk.
| (visible red or blue-violet instead of infrared)
* **Optical Disks**
* DVD technology
38
# **Computer Storage**
* **Optical Disks**
Each layer on a DVD can hold approximately
4.7 GB.
39
# **Computer Storage**
— Like other magnetic media,
is nonvolatile, and, under proper storage conditions, the data can be stored indefinitely.
* **Magnetic Tapes**
tape
40
# **Computer Storage**
Generally, full system backups are made to `____` and are moved to off-site locations for long-term storage.
* **Magnetic Tapes**
tape
41
# **Computer Storage**
is stored in a cartridge using a standard format called LTO (`______ ____ ____`).
* **Magnetic Tapes**
tape
linear tape open
42
# **Computer Storage**
When the `____` is in the `____ _____` ready for operation, it is said to be **mounted**.
* **Magnetic Tapes**
tape
tape drive
43
# **Computer Storage**
When the tape is in the tape drive ready for operation, it is said to be
* **Magnetic Tapes**
**mounted**.
44
# **Computer Storage**
have the major advantage of convenience. They are easy to mount and dismount, and small and easy to store.
* **Magnetic Tapes**
Tape cartridges
45
# **Computer Storage**
can store as much as 3 TB of `__________ ____` or 1.5 TB of `____________ ____`.
* **Magnetic Tapes**
Current tape cartridges
compressed data
uncompressed data
46
# **Computer Storage**
Current tape cartridges can store as much as `___ __` of compressed data or `___ __` of uncompressed data.
* **Magnetic Tapes**
3 TB
1.5 TB
47
# **Computer Storage**
The technique used for this type of storage and retrieval is called **data streaming**.
* **Magnetic Tapes**
48
# **Computer Storage**
* **Magnetic Tapes**
The technique used for this type of storage and retrieval is called
**data streaming**.
49
# **Computer Storage**
**Disk Controller**
These are the types of disk controllers that are used in storage devices:
* **Parallel Advanced Technology Attachment (PATA)**
* **Serial Advanced Technology Attachment (SATA)**
* **Small Computer System Interface (SCSI)**
* **Serial Attached SCSI (SAS)**
50
# **Computer Storage**
— These were the first types of hard disk drives that made use of Parallel interface standard to connect to computers.
**Disk Controller**
* **Parallel Advanced Technology Attachment (PATA)**
51
# **Computer Storage**
These types of drives are referred to as the Integrated Drive Electronics (IDE) and Enhanced Integrated Drive Electronics (EIDE) drives.
**Disk Controller**
* **Parallel Advanced Technology Attachment (PATA)**
52
# **Computer Storage**
**Disk Controller**
* **Parallel Advanced Technology Attachment (PATA)**
These types of drives are referred to as the `__________ _____ ___________` (`___`) and `________ __________ _____ ___________` (`____`) drives.
Integrated Drive Electronics (IDE)
Enhanced Integrated Drive Electronics EIDE
53
# **Computer Storage**
These drives store data by the use of magnetism. The internal structure is made of mechanical moving parts.
**Disk Controller**
* **Parallel Advanced Technology Attachment (PATA)**
54
# **Computer Storage**
Western Digital introduced PATA drives back in 1986.
**Disk Controller**
* **Parallel Advanced Technology Attachment (PATA)**
55
# **Computer Storage**
**Disk Controller**
introduced `____` drives
back in 1986.
* **Parallel Advanced Technology Attachment (PATA)**
Western Digital `__________` PATA drives back in `____`.
56
# **Computer Storage**
**Disk Controller**
can go up to 133MB/s, and a maximum of two (2) `_______` can be connected to a `_____ _______`.
* **Parallel Advanced Technology Attachment (PATA)**
Data transfer rate can go up to `___ ____`, and a maximum of `_____` (`_`) devices can be connected to a drive channel.
57
# **Computer Storage**
**Disk Controller**
Most of the `____________` have a provision of two (2) `________`, thus can connect a total of four (4) `____ _______` internally.
* **Parallel Advanced Technology Attachment (PATA)**
Most of the motherboards have a provision of `_____` (`_`) channels, thus can connect a total of `_____` (`_`) EIDE devices internally.
58
# **Computer Storage**
**Disk Controller**
make use of 40- or 80-`____ ______ _____` to transfer multiple `____ __ ____` simultaneously in parallel.
* **Parallel Advanced Technology Attachment (PATA)**
PATA drives make use of `___`- or `___`-wire ribbon cable to transfer `________` bits of data simultaneously in parallel.
59
# **Computer Storage**
**Disk Controller**
— These hard drives have replaced the `____` drives in desktop and laptop computers. The `__________` physical difference between the two is the `_________`, although their `______ __ __________` to a computer is the same.
* **Serial Advanced Technology Attachment (SATA)**
— These hard drives have replaced the PATA drives in `_______` and `______ _________`. The main physical `__________` between the two is the interface, although their method of connection to a `________` is `_________`.
60
# **Computer Storage**
**Disk Controller**
* **Serial Advanced Technology Attachment (SATA)**
Here are some of the advantages of SATA hard disk drives over PATA:
○ It can transfer data faster by using serial signaling technology.
○ The cables are thinner and more flexible than PATA cables.
○ It has a 7-pin data connection with cable limit of 1 meter.
○ It does not share bandwidth because there is only one (1) disk drive allowed per SATA controller chip on the computer motherboard.
○ It consumes less power. It only requires 250 mV as opposed to PATA's 5V.
61
# **Computer Storage**
**Disk Controller**
— These are quite simiilar to `___ ____ ______`, but these make use of parallel interface standards developed by the `________ ________ _________ _________` (`____`) for attaching devices to computers.
* **Small Computer System Interface (SCSI)**
— These are quite simiilar to IDE hard drives, but these make use of `________ _________ _________` developed by the American National Standards Institute (ANSI) for `_________ _______` to `_________`.
62
# **Computer Storage**
**Disk Controller**
can be connected internally or externally. Devices that are `____________` in an `____` can be daisy-chainned and has to be terminated at the `_________` through the use of a special terminating `____` designed for `____` devices.
* **Small Computer System Interface (SCSI)**
SCSI drives can be connected `__________` or `__________`. Devices that are connected in an SCSI can be `______________` and has to be `__________` at the end through the use of a `_______ ___________` plug designed for SCSI devices.
63
# **Computer Storage**
**Disk Controller**
can support devices
## Footnote
like `__________ ____`, `______`, and `_______`.
* **Small Computer System Interface (SCSI)**
SCSI can `_______` devices
## Footnote
like multi-hard disk, CD-ROM, and scanner.
64
# **Computer Storage**
**Disk Controller**
It can also connect as many as 30 `_______` and `___________` by daisy chain. It is the most `__________` for an entity that needs enormous `________`.
* **Small Computer System Interface (SCSI)**
It can also connect as many as `__` devices and peripherals by `_____ _____`. It is the `_____` suitable for an entity that needs `________` capacity.
65
# **Computer Storage**
* **Small Computer System Interface (SCSI)**
Here are some of their advantages:
**Disk Controller**
○ Faster and very reliable.
○ Good for 24/7 operations
○ Have better scalability and flexibility in arrays
○ Well-adapted for storing and moving large amounts of data.
66
# **Computer Storage**
**Disk Controller**
— It is a new `__________` of `____ ____` attachment.
* **Serial Attached SCSI (SAS)**
— It is (a + 'n?') `___` technology of hard disk `__________`.
67
# **Computer Storage**
**Disk Controller**
It combines the advantages of current parallel `____` and `______ ________` technology, set `______ _____________` as the protocol infrastructure, adopts `____`-3 extended `___________ ___`, and is compatible with `____` devices.
* **Serial Attached SCSI (SAS)**
It combines the `_____________` of `_______ ________` SCSI and serial attached technology, `___` serial communication as the `________ ______________`, `______` SCSI-3 `________` instruction set, and is `____________` with SATA devices.
68
# **Computer Storage**
**Disk Controller**
It is a multi-level `_______ _______ _____`; in fact, `___` disk is a disk `________` this interface technology.
* **Serial Attached SCSI (SAS)**
It is a `___________` storage devices stack; in fact, SAS disk is a disk `________` this interface technology.
69
# **Computer Storage**
**Disk Controller**
Here are its characteristics:
— It reduces the address conflicts and the deceleration of daisy chain. It provides a special signal channel to each device to ensure the maximum bandwidth; Data operation under full duplex ensures the most effective data handling capacity.
— Thinner cable matches smaller connector.
— It can connect more disk devices simultaneously.
* **Serial Attached SCSI (SAS)**
○ *Better Performance*
○ *Simple Cable Link*
○ *Better Scalability*
70
# **Computer Storage**
**Disk Controller**
* **Serial Attached SCSI (SAS)**
Here are its characteristics:
— It reduces the address conflicts and the deceleration of daisy chain. It provides a special signal channel to each device to ensure the maximum bandwidth; Data operation under full duplex ensures the most effective data handling capacity.
○ *Better Performance*
71
# **Computer Storage**
**Disk Controller**
* **Serial Attached SCSI (SAS)**
Here are its characteristics:
— Thinner cable matches smaller connector.
○ *Simple Cable Link*
72
# **Computer Storage**
**Disk Controller**
* **Serial Attached SCSI (SAS)**
Here are its characteristics:
— It can connect more disk devices simultaneously.
○ *Better Scalability*
73
# **Computer Storage**
The hard drives, like any other peripheral devices, are connected to the `__________ _____` through a `__________`. In the early stages, controllers were mainly used to bridge between the `___` protocol and the `______` protocol.
**Performance Enhancements**
The hard drives, like any other peripheral devices, are `_________` to the computer's buses `_______` a controller. In the `_____ ______`, controllers were `______` used to `_____ _______` the bus `________` and the device `________`.
74
# **Computer Storage**
**Performance Enhancements**
Here are some of the technics employed in enhancing storage devices:
* **Larger blocks**
* **Pre-fetch**
* **Access algorithms**
* **Disk array**
75
# **Computer Storage**
**Performance Enhancements**
The controller can read larger quantities of data from the disk as compared with the amount requested by the application. The additional data is stored in buffers within the controller.
* **Larger blocks**:
76
# **Computer Storage**
**Performance Enhancements**
The controller can identify the application's patterns of behavior. When an application reads the sectors sequentially, the controller can read the next blocks even before they are requested.
* **Pre-fetch** (*read ahead*):
77
# **Computer Storage**
**Performance Enhancements**
These are usually implemented by the operatingn system. These are included in the discussion to provide an elaborated explanation and a complete view of performance enhancement methods.
* **Access algorithms**:
78
# **Computer Storage**
**Performance Enhancements**
This is a technology that increases the size of the single disk as well as its speed, reliability, and survivability.
* **Disk array**:
79
# **Computer Storage**
**Storage Access Algorithms**
There are various algorithms that are implemented by the operating system to optimize the disk access time.
Some of these algorithms include the following:
* **First Come First Served (FCFS) algorithm**
* **Shortest Time First (STF) algorithm**
* **SCAN (elevator algorithm)**
* **Circular SCAN (C-SCAN)**
* **C-LOOK**
80
# **Computer Storage**
**Storage Access Algorithms**
handles the requests based on their arrival order. The first request will be served first, followed by the second request, and so forth.
* **First Come First Served (FCFS) algorithm**
81
# **Computer Storage**
**Storage Access Algorithms**
handles the requests based on their distance from the current head location. The first request to be handled is the closest one.
* **Shortest Time First (STF) algorithm**
82
# **Computer Storage**
**Storage Access Algorithms**
is where the head starts at one (1) end of the disk (usually at the first cylinder) and, while moving to the other end, handles all the requests found along the way.
* **SCAN (elevator algorithm)**
83
# **Computer Storage**
**Storage Access Algorithms**
When the head reaches the end of the disk, it starts its movement backward following the same mechanism, only this time the sorted numbers are handled from the largest downward.
* **SCAN (elevator algorithm)**
84
# **Computer Storage**
**Storage Access Algorithms**
is very similar to SCAN but with a minor change. The head starts at one (1) end (usually at the beginning of the disk) and, while moving at the end of the disk, handles all the requests it finds.
* **Circular SCAN (C-SCAN)**
85
# **Computer Storage**
**Storage Access Algorithms**
is an improvement of C-SCAN. Unlike C-SCAN, which moves from the beginning of the disk to its end (even if there are no additional requests near the end), the head moves forward untile it finds the request with the larger cylinder number.
* **C-LOOK** algorithm
86
# **Computer Storage**
can be used to reduce the overall data access time by sharing the data among multiple disks. It can also be used to increase system reliability by providing storage redundancy. One useful type of disk array is RAID (Redundant Array of Inexpensive Disks [some people say Redundant Array of Independent Disks]).
**Disk Arrays**
A **disk array (drive array)**
87
There are `_____` (`_`) standard methods of implementing a disk array:
**Disk Arrays**
two (2)
* **Mirrored array**
* **Striped array**
88
# **Computer Storage**
**Disk Arrays**
— It consists of two (2) or more disk drives. In a mirror array, each disk stores exactly. In a mirror array, each disk stores exactly the same data. During reads, alternate blocks of the data are read from different drives and then combined to reassemble the original data. Thus, the access time for a multiblock read is reduced approximately by a factor equal to the number of disk drives in the array.
* **Mirrored array**
89
# **Computer Storage**
**Disk Arrays**
— It uses a slightly different approach in which a file segment to be stored is divided into blocks. Different blocks are then written simultaneously to different disks. This effectively multiplies the throughput rate by the number of data disks in the array. It also requires a minimum of three (3) disk drives; in the simplest configuration, one (1) disk drive is reserved for error checking.
* **Striped array**
90
# **Computer Storage**
refers to remote data storage done over a computer network.
**Cloud Storage Technology**
**Cloud storage**
91
# **Computer Storage**
Instead of using an external device connected to the computer,
makes use of storage devices located elsewhere and connected by the Internet or some other type of network connection.
**Cloud Storage Technology**
**Cloud storage**
92
# **Computer Storage**
These are the `_____` (`_`) standard methods of implementing a disk array:
**Cloud Storage Technology**
two (2)
* **Storage Attached Network (SAN)**
* **Network Attached Storage (NAS)**
93
# **Computer Storage**
**Cloud Storage Technology**
— It is a local area network intended to handle large amounts of data and provide fast transfer rates to organization data. One of the advantages of using SAN is that it provides the user community with simple, coherent access to common corporate information.
* **Storage Attached Network (SAN)**
94
# **Computer Storage**
**Cloud Storage Technology**
— It represents a different approach to storing data in the network. In NAS, the storage resources are connected directly to the network. This approach has been around for a long time as a method for sharing files. Contrary to the SAN approach, which allows access only on a block basis, NAS relates to the whole files.
* **Network Attached Storage (NAS)**
