Specifications for the Matsushita DVD-RAM UJ-840S

Long before the Japanese electronics company began using the Panasonic name in 2008, many of its products bore the Matsushita nameplate. One such product was the UJ-840S optical drive. Also branded as Matshita or Matshita Panasonic, this CD/DVD drive could be found on laptops from major computer manufacturers such as HP, Sony and Panasonic itself. Although Panasonic has stopped making the UJ-840S, it may still be available for purchase at a few online retail outlets.


The Matsushita UJ-840S had the "Super Multi" designation, which meant that in addition to playing prerecorded CDs and DVDs -- known as CD-ROM and DVD-ROM, respectively -- users could play and record the following optical disc formats: CD-R/RW, DVD-RAM, DVD-R/RW and DVD+R/RW. The UJ-840S was also compatible with dual-layer DVDs, which have two recordable dye layers for storing data, instead of one. Consequently, dual-layer DVDs can store twice as much data as single-layer ones.


The Matsushita UJ-840S played and recorded -- or "read" and "wrote" -- DVDs at a slower speed than it did CDs. The optical drive could read CD-ROMs at 24x, while the reading speed for DVD-ROMs was 8x. In terms of writing performance, CD-Rs and CD-RWs had rates of 24x and 10x, respectively. Of the recordable DVD formats, the UJ-840S could record DVD+/-Rs the fastest, at a rate of 8x. DVD-RAMs and DVD+/-RWs were next in line, with rates of 5x and 4x, respectively. Because of their larger data storage capacity, dual-layer DVDs had the slowest writing speed, at 2.4x.


Manufacturers connected the Matsushita UJ-840S to their computers with its Integrated Drive Electronics connector. Retroactively known as Parallel AT Attachment, or Parallel ATA, the interface adhered to ATA Packet Interface standards. The UJ-840s had a 2-MB buffer, a small section within the drive for temporarily storing data for faster access.

Physical Characteristics

The Matsushita UJ-840S used a tray-loading mechanism for playing optical discs. The optical drive had an eject button that pulled out a motorized tray when pressed. The user could then place the disc on the tray. Weighing almost 0.5 lbs., the UJ-840S used the traditional 5.25-inch form factor. It had a length of 127 mm, height of 12.7 mm and width of 128 mm.