File Organization & Storage Quiz

File Organization & Storage

• Files are collections of data stored permanently.
• Files are identified by filenames.
• Files can be documents, pictures, audio/video streams, applications, or other data collections.
• Data stored on disks, hard drives, tapes, optical media, or other non-volatile storage media.

File Operations

• Opening a file connects logical file to physical file.
• Closing a file disconnects the logical and physical file.
• Reading and writing are basic I/O operations on files.
• Seeking refers to accessing a specific location within a file.
• Detecting the end of a file checks for file termination.
• Detecting I/O error checks for any I/O issues.

Good File Structure Characteristics

• Quick access to large amounts of data.
• Reduction in disk access numbers.
• Managing file growth by splitting data collections.

Why Organize Files?

• Grouping related information for quick retrieval.
• Minimizing disk accesses for efficient data retrieval.
• Ideal to retrieve data with one disk access; minimizing disk access where possible.

File Types

• Refer to the slideshow for a list of file types.

Elements of a Computer File

• Records - collections of related fields representing data entries. Examples include student records in a class scoresheet with details like admission number, name, total marks, and position.
• Fields - single character or collections representing data. Example, a student's admission number.
• Characters - the smallest unit in a file representing a letter, number, or symbol. Character coding schemes use 7 or 8 bits.

File Compression

• Compressed files are archives of one or more files, reduced in size.
• Example: AAABBBCC compressed to 3A5B2C.

Compression Sample

• Examples of text compression are in the slides.

Compression File Types

• Refer to the slideshow for a list of compressed file types.

Experiment on File Compression

• Compressing a compressed file may or may not reduce the file size further.
• Methods for compressing files on phones are not detailed.

Part 2: File Storage Media and Technologies

• Identifying storage media (e.g., hard disk, solid-state drive, USB flash drive, memory card, optical disc, magnetic stripe card, smart card, RFID tag, network-attached storage, cloud storage) currently available.

Other Storage Types

• Magnetic stripe cards have a magnetic stripe for storing data.
• Smart cards store data on an embedded circuit.
• RFID tags consist of an antenna and a memory chip to transfer information wirelessly.
• An NFC-enabled device incorporates an NFC chip and an antenna to transmit data.
• Network-attached storage (NAS) is a server for providing storage to network devices.
• Cloud storage services, like Dropbox, Google Drive, iCloud, OneDrive, and BaiduYun, provide online storage.

Application of RFID

• RFID technology is used in inventory management, access control, animal tracking, personnel tracking, identification, and asset tracking.

Other Types of Storage

• NFC-enabled devices use NFC chips and antennas to transmit data.

Network-Attached Storage (NAS)

• NAS is a specialized network server for providing storage.

Cloud Storage Services

• Cloud storage services like Dropbox, Google Drive, iCloud, OneDrive, and BaiduYun offer online storage.
• Features advantages/disadvantages of cloud storage (e.g., accessibility, sharing, backup, and cost).

Enterprise Storage

• Enterprise hardware is designed for large-scale data management and storage demands.
• RAID (Redundant Array of Independent Disks) enhances data efficiency and availability in enterprise settings.

RAID Technology

• RAID technology improves performance by placing data in multiple disks and allowing overlapping file I/O.
• RAID controllers (hardware) and software-based virtualization options are possible.
• Example RAID types (RAID 0, RAID 1, RAID 5, RAID 1+0)

RAID 0

• Data is split into blocks and written across multiple drives.

RAID 0-Advantages

• Increased I/O performance; no overhead from parity controls; full utilization of storage capacity.

RAID 0-Disadvantages

• Data loss in case of a drive failure; not ideal for continuous data access scenarios.

RAID 1

• Mirroring data on two or more drives.

RAID 1 Disadvantages

• Reduced effective storage capacity (50% due to data duplication), higher expense than RAID 5.

RAID 5

• Block-level striping with parity information spread across drives.

RAID 5 Advantages

• Continued functionality even with a drive failure; data is available even when recovery occurs.

RAID 5 Disadvantages

• Rebuild times can take days; additional drive failure during rebuild may result in data loss.

RAID 1+0

• Combines RAID 1 and RAID 0 for better performance and fault tolerance.

RAID 1+0 Advantages

• Fast rebuild time in case of drive failure and high performance; suitable for intensive write operations.

RAID 1+0 Disadvantages

• Half of storage capacity is used for mirroring; more costly than RAID 5.

Summary

• The summary recaps the covered topics about definitions of file, I/O operations, good file structure, file elements, storage types, different compression types and RAID types.