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| Chapter 3 Display/Operation Panel |
Page 3 - 16 |
| ARRAY INFORMATION |
CAPACITY | Displays the logical block number of the last data block in the array. A value | |
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| followed by 'indicates a decimal number; a value followed by +indicates a |
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| hex number. |
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| To calculate the capacity of the array, add one to the number displayed. For |
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| example, a display with 'in an array formatted with 512 as the |
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| sector size indicates that the array's capacity is 4,207,837 blocks of 512 bytes |
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| each. |
INITIATOR | A | |
| INFO | as initiators of SCSI commands, and some acting as targets. The array is always |
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| a target. |
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| The SCSI protocol allows targets and initiators to negotiate the width of the |
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| bus to be used when transferring data, the transfer rate, and also whether the |
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| transfer will be synchronous or asynchronous. This information is stored by the |
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| array for each initiator on the SCSI bus under Array Information. |
P is the Transfer Period
O is the Synchronous Offset
W indicates that a wide
N indicates that a narrow
To determine the Transfer Rate from the Transfer Period:
1.Translate the hexadecimal Transfer Period into decimal. For example, 19H equals decimal 25.
2.Multiply the decimal value by 4 to get the Transfer Period in nanoseconds (25 x 4 = 100).
3.Take the reciprocal of this value to get the Transfer Rate in Megahertz
4.Multiply by the bus width (1 or 2 bytes) to get the bus burst transfer rate, e.g., 10 MHz x 2 bytes wide = 20MB/second.
Note Because the 6510 employs Wide Ultra SCSI technology, the SCSI specification requires a slight variation to the computations above. Wide Ultra SCSI technology is designated as 0CH or decimal 12, when in fact it is slightly longer at 12.5. When the designated period is multiplied by 4 to get the Transfer Period in nanoseconds, the result is 48. In reality it is 50, which is the value whose reciprocal 1/50 nanoseconds equals 20 Megahertz (20MB/ second).
21020690 B | 6500 Disk Array User’s Guide |