LVD vs HVD

[Eric Firkey]

Can anyone tell me the advantages or disadvantages of LVD vs HVD? I am especially interested in finding any potential problems with backing up an HVD interface library with an LVD library.

[Eugeny Brychkov]

They are electrically incompatible. You can not connect LVD device to HVD HBA without using SCSI bus convertor (for example, http://www.paralan.com/mh19.html ).
HVD: +cable length, +low interference, -speed (max 40mb/s), -incompatible with SE;
LVD: +speed (up to 320mb/s), +compatible with SE (whole bus becomes SE), -special cable may be needed
Eugeny

[CA698399]

Hi Eric,

Here's some additional information regarding LVD vs. HVD:
http://www.storagesearch.com/lvdart.html
http://www.pcguide.com/ref/hdd/if/scsi/protDiff-c.html
http://www.seagate.com/support/kb/disc/ultra2.html
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xc75d0fe6d0f7d61190050090279cd0f9,00.html

[BR722982]

When we were installing new tape drives the main disadvantage to HVD is that it is a dead end path. All new development is towards LVD.

[BR706671]

key practical differences are:

HVDS is slower but supports longer cable length

often older unix servers use HVDS, most PC servers use LVDS.

watch out for differing cable plugs and cable specifications -- use multimode cabling.