50 Questions
What is the main advantage of holographic storage?
Tremendous data densities are possible due to the three-dimensional nature.
What is the function of cantilevers in IBM's Millipede device?
Record a binary 1 by pressing a heated tip into a polymer substrate.
What is the role of CNTs (carbon nanotubes) in data storage?
Act as switches, opening and closing to store bits.
What is the advantage of memristors in data storage?
Combine resistor properties with memory, allowing controlled resistance for data storage.
What is Amdahl's Law related to?
The impact of I/O on performance.
What are the four I/O control methods?
Programmed I/O, Interrupt-based I/O, DMA (Direct Memory Access), and Channel I/O.
What are the components of I/O systems?
Memory blocks, cabling, control circuitry, interfaces, and media.
What is the principal form of durable storage?
Magnetic Disk.
What are the performance metrics for magnetic disk?
Seek time, rotational delay, and reliability estimates.
What are the components of a bus?
Control lines, a clock, and data lines.
What is the primary function of computer systems in relation to data?
Data storage and retrieval
What is the effect of sluggish I/O throughput in systems involving virtual memory?
Ripple effect
What law estimates the performance improvement expected when upgrading a system component?
Amdahl's Law
What is an I/O architecture?
A subsystem of components that moves coded data between external devices and a host system
What are the five general ways to control I/O operations?
Programmed I/O, Interrupt-Driven I/O, Memory-Mapped I/O, Direct Memory Access (DMA), and Channel I/O
What is the purpose of interrupt vectors in I/O operations?
To determine the executed code whenever an interrupt occurs
What is the advantage of programmed I/O?
Allows the CPU to do other things until I/O is requested
What is the characteristic of memory-mapped I/O?
Shares memory addresses between I/O devices and program memory
What is the primary way that block I/O devices handle bytes?
in groups
What type of I/O connection is most efficient for block I/O systems?
DMA or channel I/O
What is the main advantage of serial data transmission over parallel data transmission?
it requires fewer conductors and is less susceptible to attenuation
What type of data is serial transmission interfaces particularly suited for?
time-sensitive (isochronous) data such as voice and video
What is the main advantage of magnetic disks over other forms of durable storage?
they offer large amounts of durable storage that can be accessed quickly
Why are disk drives called random (or direct) access storage devices?
because blocks of data can be accessed according to their location on the disk
What is the primary component of a hard disk drive that stores data?
platters
How are data blocks addressed on a hard disk drive?
by their cylinder, surface, and sector
What is the main difference between serpentine and helical scan recording methods?
How the read/write head interacts with the tape.
What is the Linear Tape-Open (LTO) standard?
A linear digital tape format with openly available specifications.
What is the data transfer rate of LTO Gen 5 tapes without compression?
208MB per second.
What is the main purpose of RAID (Redundant Array of Independent Disks)?
To address problems related to disk reliability, cost, and performance.
What is RAID 0, and what is its main advantage?
RAID 0 is a configuration where data is written in blocks across the entire array, and its main advantage is improved performance.
What is disk mirroring, and what is its main advantage?
Disk mirroring is a configuration where two matched sets of disks contain the same data, and its main advantage is 100% redundancy.
What is the purpose of Hamming code drives in RAID configurations?
To provide error correction for the data drives.
What is the main benefit of using multiple error correction levels in LTO tapes?
Superior reliability.
What are Enterprise SSDs used for in government and industry?
Save energy and provide improved data access
What is the primary use of Magnetic Tape?
Archival medium
What is the main benefit of using RAID?
Improves disk system performance and reliability
What is RAID 5 characterized by?
Distributed parity for concurrent access
What is the key feature of RAID 6?
Protects against dual disk failure
What is RAID DP known for?
Better performance than RAID 6
What is the Data Retrieval Challenge in data storage?
Locating data after it’s stored
What type of storage technologies may replace magnetic disks in the future?
Biological, holographic, CNT, memristor, mechanical
What causes moving parts to wear out in Traditional Hard Disk Drives (HDDs)?
Fragile moving parts
What type of memory is used in Solid State Drives (SSDs)?
Flash memory
What is the term for the time it takes for the right sector to spin under the read/write head in HDDs?
Rotational Delay
What determines the lifespan of an HDD?
Design life
How do SSDs compare to HDDs in terms of access time and transfer rates?
SSDs are significantly faster
What is the approximate difference in speed between SSDs and onboard RAM?
A factor of around 100,000
What is the characteristic of SSDs that makes them similar to hard disk drives?
Block-addressable
What is the approximate range of updates to a block in flash memory?
Between 30,000 and 1,000,000
Study Notes
Block I/O Devices and Data Transmission Modes
- Block I/O devices handle bytes in groups
- Most mass storage devices (disk and tape) are block I/O devices
- Block I/O systems are most efficiently connected through DMA or channel I/O
- Data transmission modes: parallel and serial
- Parallel data sending: multiple bits are transmitted simultaneously, requires one conductor for each bit
- Serial data sending: one bit at a time, requires fewer conductors, less susceptible to attenuation
Disk Technology and Hard Disk Drives (HDDs)
- Magnetic disks offer large amounts of durable storage that can be accessed quickly
- Disk drives are called random (or direct) access storage devices
- HDD components: platters, tracks, and read/write heads
- Data blocks are addressed by their cylinder, surface, and sector
- Advantages: low cost, disadvantages: slow compared to main memory
RAID (Redundant Array of Independent Disks)
- Addresses problems related to disk reliability, cost, and performance
- Data is distributed across multiple disks, with additional disks added to provide error correction (redundancy)
- RAID levels: RAID 0, 1, 2, 3
- RAID 0: striping, no redundancy
- RAID 1: disk mirroring, 100% redundancy
- RAID 2, 3: error correction using Hamming code and striping
Optical Disks and Magnetic Tape
- Optical disks: high storage capacity at a low cost (CD-ROM, DVD, WORM)
- Magnetic tape: widely used as an archival medium
- Linear Tape-Open (LTO) standard: a collaborative effort by HP, IBM, and Seagate
- LTO offers multiple error correction levels for superior reliability
Enterprise SSDs and Future Data Storage Technologies
- Enterprise SSDs: save energy and provide improved data access for government and industry
- Future data storage technologies: biological, holographic, CNT, memristor, mechanical
- Holographic storage: uses laser beams to etch a three-dimensional hologram onto a polymer medium
- Micro-ElectroMechanical Storage (MEMS): uses cantilevers to record binary data onto a polymer substrate
This quiz covers the basics of block I/O devices, including mass storage devices and their efficient connection methods. It also explores data transmission modes, including parallel and serial transmission.
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