問74
頻出度★★☆
LANに直接接続して使用するファイルサーバ専用機を何と呼ぶか。
平成24年度 春期 ITパスポート試験 問74
テクノロジ系システム構成要素 › システムの構成
This question's explanation and your answers so far.
解説
問 74
Incorrectア
ATA (AT Attachment) is an interface standard for connecting storage devices such as hard disks to the computer itself, and Serial ATA (SATA), which uses serial transmission, is the mainstream form today. It is no more than the name of a standard that defines the wiring and connection method inside a PC. It is neither a device that connects to a LAN nor a dedicated file server machine, so it cannot be the answer to this question.
- イ
正解 The correct answer is “イ”, NAS. NAS stands for Network Attached Storage, that is, storage that is attached to a network. It is a dedicated machine that connects directly to the network with a LAN cable and whose use is narrowed down to file sharing (file server) functions only. It is sold as a product that already contains storage devices such as hard disks or SSDs together with a minimal operating system that handles file sharing protocols. From a user's PC, it appears as a shared folder on the network through standard file sharing protocols — SMB/CIFS on Windows and NFS on UNIX-based systems. Compared with building a file server by installing an operating system on a general-purpose server machine, a NAS can be put to use simply by plugging it into the LAN and doing the initial setup from a browser, and both the management effort and the cost are smaller. This is its main advantage. NAS is the only term that satisfies both conditions in the question at the same time — “connected directly to a LAN” and “a dedicated file server machine” — so “イ” is the correct answer. Note also that while NAS is accessed on a file-by-file basis, the method of accessing storage on a block-by-block basis over a dedicated high-speed network is called SAN (Storage Area Network); it is a good idea to learn the two as a contrasting pair.
Incorrectウ
RAID (Redundant Arrays of Inexpensive Disks) is the name of a technique in which several magnetic disks are combined and handled as if they were a single disk unit, in order to raise reliability (redundancy) and performance. There are several configuration levels: RAID0 (striping) for higher speed, RAID1 (mirroring) for fault tolerance through duplication, and RAID5, which uses distributed parity so that data can be restored even if one drive fails. RAID is often used inside a NAS as well, but RAID itself is not the name of a piece of equipment, nor is it a term that assumes a LAN connection, so it is wrong.
Incorrectエ
SCSI (Small Computer System Interface) is an interface standard for connecting peripheral devices such as hard disks, optical drives, and scanners to a computer, and one of its characteristics was that several devices could be daisy-chained onto a single bus. This too is only the name of a standard for attaching devices to the computer itself, and it does not refer to a dedicated file server machine that connects directly to a LAN, so it is wrong.
ここがポイント
- NAS = a dedicated file server machine used by connecting it directly to a LAN (network attached storage). It provides file-level access through file sharing protocols such as SMB/CIFS and NFS, and should be learned in contrast with SAN, which provides block-level access over a dedicated high-speed network.
- Sort confusing abbreviations by whether each one is a “standard”, a “technique”, or a “device” — ATA and SCSI are interface standards that connect the computer to peripheral devices, RAID is a technique that uses multiple disks to raise redundancy and performance, and only NAS refers to an actual device that attaches to a network.
用語