6.1.2 Data or Audio Specific Storage  To effectively manage and maintain digital audio it is necessary to transform it to a standard data format. Data formats are the file types, such as .wav, BWF, or AIFF, which computer systems recognise. These files, unlike audio specific carriers, technologically define the limits of their own content and are generally encoded in such a way that a loss of data is recognised and remedied by the host system. IASA recommends the use of BWF as defined in Section 2.8 File Formats.  Audio specific recording formats which have been available in the past include DAT (Digital Audio Tape) and CD-DA (Compact Disc-Digital Audio). DAT, though once largely used for the remote or field recording of 16 bit, 48 kHz audio is now an obsolete recording system. IASA recommends that any significant content recorded on DAT tape be transferred to a more reliable storage system in accordance with the guidance provided in section 5.5 Reproduction of Digital Magnetic Carriers.  The recordable compact disc can be used to record audio in either audio-only (CD-A or CD-DA) or data (CD-ROM) formats. In CD-DA format the encoded digital audio resembles an audio stream and so does not have the advantages of a closed file such as might be recorded on the CD-ROM formatted disc. In the latter though, less data can be stored on the same amount of disc space. IASA does not recommend recording audio in CD-DA form as a preservation target format. There are considerable risks associated with using a recordable CD as a target format in any form and those risks are outlined in Chapter 8 Optical Disks: CD/DVD Recordable. The ever reducing prices and increasing reliability of data management and storage systems make media specific storage approaches, such as CD-R, unnecessary, or at least uneconomic.