Sony DDS-4, Product Description Manual

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2 - 6 SONY SDT-10000/SDT-11000 DDS Tape Drive
2. SPECIFICATION
2. 3 PERFORMANCE SPECIFICATION
The data capacity, data transfer rate and data reliability specifications in this chapter require the media to conform to the
DDS-4 Media Specification and also require the drive and media to remain within their respective operating and non-
operating environmental specifications. The specifications below also assume that the C3 ECC frame is generated on
writing and used as necessary on reading, and further assumes that read-after-write rewrites are used as necessary on
writing.
2. 3. 1 Data Capacity
The native (uncompressed) capacities of different length cartridges are as follows. Note that 60 m and 90 m cartridges
are automatically written in DDS-1 format, only 120 m cartridges are written in DDS-2 format, and only 125 m car-
tridges are written in DDS-3 format, and only 150 m cartridges are written in DDS-4 format
Length Format Native Capacity
60 m DDS-1 1.3 GB typical
90 m DDS-1 2.0 GB typical
120 m DDS-2 4.0 GB typical
125 m DDS-3 12.0 GB typical
150 m DDS-4 20.0 GB typical
The SDT-10000/SDT-11000 includes a data compression capability. When data compression is enabled that the drive
capacity can increase typically twice. The efficiency of the data compression depends on the actual data that is being
compressed and cannot be predicted precisely prior to compression.
Sustained transfer rate
Format W/O Compression W/Compression *1
DDS-1 778 KB/S 1556 KB/S
DDS-2 778 KB/S 1556 KB/S
DDS-3 2360 KB/S 4720 KB/S
DDS-4 2360 KB/S 4720 KB/S
2. 3. 2 Data Transfer Rate
2. 3. 2. 1 Sustained Data Transfer Rate To and From Tape
The sustained transfer rates to and from the tape are as follows. For this sustained rate to be achieved, the drive must be
streaming. There may be some dependency on the host for this to be achieved.
*1 This is assuming 2:1 Compression ratio.
The degree of data compression attained while recording data varies according to system environment and data type.
2. 3. 2. 2 Burst Data Transfer Rate To and From the SCSI Bus
The SDT-10000/SDT-11000 will transmit and receive data bursts to and from the SCSI bus at a maximum burst rate of
14 megabytes per second, using WIDE SCSI asynchronous transfers and 40 megabytes per second, using WIDE SCSI
synchronous transfers.
2. 3. 3 Initialize Time
Initialize Time means the period from the time the drive is powered on to the time when the drive is ready and waiting
for a SCSI command such as INQUIRY or TEST UNIT READY.
Initialize Time is less than 1 seconds.
Note: The drive will respond with BUSY status until the completion of the Initialize Time.
Note: The Initialize Time does not include the time necessary for drive diagnostics to complete and the drive to become
ready for tape insertion.