OS File Management And I/O: Quiz!

Records are treated as a unit means that when dealing with a database, all the information related to a particular record is considered together. This means that any changes or updates made to the record will affect all the fields and attributes associated with it. Treating records as a unit ensures data integrity and consistency within the database. Therefore, the correct answer is True.

A basic element of data in a file is a field. A field is a specific piece of information within a record that represents a single attribute or characteristic. It can hold a value or multiple values related to that attribute. For example, in a database of employees, a field could be "employee name" or "employee ID." Fields are used to organize and store data in a structured manner, allowing for efficient retrieval and manipulation of information within a file.

C-SCAN is the correct answer because in this algorithm, the disk head moves from one end to the other, servicing requests along the way. Once it reaches the other end, it immediately returns to the beginning of the disk without servicing any requests on the return trip. This algorithm is commonly used in disk scheduling to optimize the movement of the disk head and reduce seek time.

Rotational latency refers to the time it takes for the desired sector of a disk to rotate under the disk head. This is the time it takes for the disk to spin until the desired sector is positioned directly under the read/write head. It is an important factor in determining the overall access time of a disk system.

File organization refers to the logical structuring of records. It involves arranging data in a systematic manner within a file, which allows for efficient storage, retrieval, and manipulation of information. This can include various methods such as sequential, indexed, or hashed file organization. By organizing files, it becomes easier to locate and access specific data, improving overall efficiency and effectiveness in data management.

Chained Allocation is a method of allocating storage space for files in a computer system. In this method, each block contains a pointer to the next block in the chain, allowing for easy traversal of the blocks. This means that the blocks do not need to be contiguous, and they can be located anywhere in the storage space. Chained Allocation is commonly used in file systems where files can grow dynamically and the location of each block is not predetermined.

A basic element of data in a file is a field. A field represents a single piece of information within a record. It can be a name, a number, a date, or any other type of data. Fields are used to organize and categorize data within a file, allowing for efficient storage and retrieval. Each record in a file consists of multiple fields, each containing a specific data value. Therefore, the correct answer is "Field".

Indexed Sequential maintains the key characteristic of the sequential file by organizing records in sequence based on a key field. This means that the records are stored in a specific order according to the values in the key field, allowing for efficient searching and retrieval of records based on this key. Additionally, the index component of the indexed sequential file helps to further enhance the performance by providing a separate data structure that allows for faster access to specific records.

In indexed allocation method, the file allocation table contains a separate one level index for each file. This means that for each file, there is a corresponding index entry in the file allocation table. Each index entry points to the location of the portions allocated to the file. This allows for efficient access to different portions of the file, as the index provides a direct mapping to the allocated portions.

LOOK algorithm is a disk scheduling algorithm in which the disk arm moves towards the final request in each direction and then immediately reverses its direction without reaching the end of the disk. This algorithm helps in reducing the average seek time by servicing the requests in a more efficient manner.

Airline reservation systems and inventory control systems typically use indexed files. Indexed files allow for efficient access and retrieval of data by using a separate index structure that contains pointers to the actual data records. This index structure enables quick searching and sorting of data, making it suitable for applications that require frequent data retrieval and updates. Sequential files, on the other hand, store data in a sequential order and do not provide efficient access to specific records. Therefore, the correct answer is indexed file.

The seek time refers to the time taken by the disk arm to move to the desired cylinder. It is a crucial factor in determining the overall performance of a disk drive. The positioning time, on the other hand, refers to the time taken to position the disk arm over the desired track. Random access time is a broader term that includes both seek time and rotational latency. Rotational latency specifically refers to the time taken for the desired sector to rotate under the disk head.

RAID 1 is a type of RAID that doesn't use parity for data protection. In RAID 1, data is mirrored onto two or more drives, creating an exact copy of the data on each drive. This means that if one drive fails, the data can still be accessed from the remaining drives. Parity is not used in RAID 1 because there is no need for it, as the data is already duplicated on multiple drives.

Indexed Sequential file greatly reduces the time required to access a single record without sacrificing the sequential nature of the file. This is achieved by using an index, which is a separate data structure that stores the addresses of the records in the file. The index allows for direct access to specific records, rather than having to sequentially search through the entire file. This improves the efficiency of accessing individual records while still maintaining the sequential organization of the file.

Chained Free portions method has negligible space overhead because there is no need for a disk allocation table. Instead, this method uses a pointer to the beginning of the chain and the length of the first portion. This means that the free space is managed by linking together consecutive free portions of memory. The pointer allows easy access to the beginning of the chain, and the length information helps in efficiently utilizing the available free space. Therefore, this method is efficient in terms of space management without the need for additional data structures like a disk allocation table.

The SCAN algorithm starts at one end of the disk and moves towards the other end, servicing requests along the way. Once it reaches the other end, the direction is reversed and servicing continues in the opposite direction. This algorithm is efficient as it reduces the average seek time by servicing requests in a continuous manner, rather than going back and forth between different parts of the disk.

RAID 6 is unique because it uses two independent distributed parity schemes. This means that it can tolerate the failure of two drives simultaneously without losing any data. The data is striped across multiple drives, and two separate parity calculations are performed, which provides an extra level of redundancy and fault tolerance. This makes RAID 6 a reliable option for data storage systems that require high levels of data protection.

Contiguous allocation is a preallocation strategy where variable size portions are used. In this strategy, the file allocation table only requires a single entry for each file, indicating the starting block and the length of the file. This means that the file is stored in consecutive blocks on the storage device, allowing for efficient access and retrieval of data.

RAID 5 is characterized by distributed parity, which means that the parity information is spread across all the drives in the RAID array. This offers redundancy and fault tolerance, as if one drive fails, the parity information can be used to reconstruct the data on that drive. This distributed parity also allows for improved performance, as the data can be read from multiple drives simultaneously.

In the "Pile" file organization, data is collected in the order in which they arrive, with each record consisting of one burst of data. This means that the records are simply added to the file as they come in, without any specific organization or structure. The data is stored in a continuous manner, with no particular indexing or sequencing applied. This type of file organization is simple and straightforward, but it can make searching and accessing specific records more time-consuming and inefficient.