1 / 6

File management

File management. access methods. logical I/O (LIOCS). physical I/O (PIOCS). device drivers. File Systems Architecture. File organization and access sequential index-sequential direct. block data. block data. block data. IBG. IBG. IRG. IRG. IBG. File sharing

roscoe
Download Presentation

File management

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. File management

  2. access methods logical I/O (LIOCS) physical I/O (PIOCS) device drivers File Systems Architecture File organization and access • sequential • index-sequential • direct

  3. block data block data block data IBG IBG IRG IRG IBG • File sharing • access rights: read, write, execute, by user classes. • File/record locking: simultaneous access • Record blocking • Logical vs physical record • unblocked vs blocked record • fixed-length vs variable-length File sharing and blocking

  4. File allocation table (FAT) • Pre allocation vs dynamic allocation • Portion size • contiguity increases performance • fixed-size portions simplify reallocation • variable-size or small fixed-size minimizes waste of unused space for overallocation • two main alternatives: • variable, large contiguous portions (performance) • small fixed portions (flexibility) • File fragmentation and reorganization File allocation

  5. strip 0 strip 1 strip 2 strip 3 strip 4 strip 5 strip 6 strip 7 strip 9 strip 10 strip 11 strip 8 strip 13 strip 15 strip 14 strip 12 Redundant Array of Independent/ Inexpensive Disks (RAID) • RAID is a set of physical disk drives viewed by the OS as a single logical drive • Data are distributed across the physical drives of an array • Redundant disk capacity is used to store parity information, which guarantees data recovery • RAID Levels: various levels of performance and redundancy • the disks are divided in strips: physical blocks, sectors, or similar • the strips are mapped round robin on the array • I/O requests can be processed in parallel

  6. Storage Management • Storage Area Network (SAN) • Building a Storage Area Network • Fiber and IP • Network Attached Storage (NAS) • SAN and NAS topology • NAS and interoperability • Comparison of SAN and NAS • SAN and NAS comparison

More Related