Direct-to-disk recording (DDR) refers to methods by which analog signals and digital signals such as digital audio and digital video are digitally recorded to optical disc recording technologies such as DVDs, and CD optical discs. Magnetic storage includes hard drives (HDD), magnetic tape such as videotape and is different than flash memory.
Direct to disk can involve permanent or semi-permanent non-volatile memory recording media. Computer hard disk drives are random access, erasable and rewritable non-volatile recording devices but have been referred to as "permanent" by some manufacturers of direct to disk systems.
Audio recording 
In 1982, New England Digital offered an optional hard disk recorder package for their Synclavier which allowed digital recording of monophonic 16-bit 50 kHz audio direct to a hard drive; this was the first digital direct to disk audio recorder available commercially. Stereo audio was not immediately available due to data input and output limitations on hard drives of that time.
Today, a majority of digital audio recording is preserved on hard disk drives.
Video recording 
- Consumer: From camcorders to digital video recorder (DVR) and set top box models like TiVo to personal computer based recorders.
- High-end consumer – Pro: non-linear editing (NLE) systems like Avid Technology video editing systems, to high-end tapeless camcorders
- Professional portable: For recording television productions/filmmaking in the field with professional video cameras in digital cinematography for digital cinema productions.
- Professional television studio: From small systems able to record 2 hours to Large multi port playout systems with a 100 hours of rec/play time
- Miniaturization of recording and storage technology for consumer video already allows the non-professional user to directly record home movies to a permanent storage medium like DVD.
- DDRs are slowly replacing Consumer: Magnetic tape based DV, Digital8, 8mm Video Format, VHS and MicroMV video tape recorders.
Professional portable 
- Professional recording equipment using DtD transfers is beginning to appear. In April 2006, Seagate announced the first professional Direct-To-Disc cinematic camera aimed at the independent film-maker (using their disc drives).
- Infinity Series by Grass Valley
- Infinity Digital Media Camcorder – Infinity Digital Media Recorder
- REV PRO Digital Media Drive-REV PRO Removable Media
Professional studio 
- Professional television studio DDRs video servers are being used to replace video tape recorders (VTR)s and VTR Cart machines, that playout television commercials and TV shows. Digital audio workstations (DAW) are used in professional audio recording studios
- AJA Systems' Ki Pro family of direct-to-disk (solid-state disk/HDD/Compact Flash) professional DVRs (http://www.aja.com/en/products/ki-pro-family/)
- Blackmagic Design's HyperDeck Studio line of professional SSD DVRs (http://www.blackmagic-design.com/products/hyperdeckstudio)
- The Media Pool (1994)- Disk Recorder by Broadcast Television Systems Inc. (BTS) was the first Professional Studio DDR. Received the Outstanding Achievement in Technical/Engineering Development Awards from National Academy Of Television Arts And Sciences in 2000–2001 for Pioneering developments in shared video-data storage systems for use in television video servers - Philips/Thomson.
- Profile from Tektronix Models: PDR200-(1996), PDR300, PDR400
- sQ Class of Servers and sQ Clients
- Grande Vitesse Systems (GVS):
- Profile GVS9000 2XU Pro, GVS9000 1XU Pro, GVS90000 7XU and other models of DDRs
- Nomadic 1U 12xPro 24 hrs Uncompressed 10-bit 1080p Media Storage
- Metropolis Media Servers
- 9000CTR Dual Uncompressed HD Controller
- Grass Valley:
- Profile PVS3000, PVS3500 and other models of DDRs
- K2 Media Servers and Media Clients
- Profile XP Video Servers
- Profile XP Open SAN System
- M-Series intelligent video digital recorder (iVDR)
- Turbo intelligent digital disk recorders (iDDRs)
- Digitale Videosysteme (DVS):
- DVS Clipster DDR
- DVS 2K Pronto DDR
- CarbonHD digital disk recorder
- The Digital video is stored on a storage area network (SAN) hard disk array.
- Each year hard disk storage capacity gets larger and is able to hold hours of movies on Tera Byte systems.
Advantages of DDR over tape 
- Quicker into the non-linear editing systems: no need to digitise
- The hard disks can store more than most video tapes
- Tapes and VTRs are expensive to maintain for the higher video data rates
Disadvantages of DDR over tape 
- Hard disks are more expensive than video tapes
- Hard disks fail more frequently than video tapes
- Not practical to store a bank of hard drives for long term video storage.
See also 
- Synclavier history
- "JVC Everio series hard disc handi-cams". JVC. Retrieved 2006-11-22.
- "Seagate Hard Drives Enable World's First Digital Cinema Camera With Direct-To-Disc. Recording" (Press release). Seagate. March, 2005. Retrieved 2006-11-22.
- "Media Pool tests the tapeless waters. (BTS digital disk-based recorder)". Archived from the original on 2007-10-04. Retrieved 2008-01-27.