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rally
New User
Joined: 28 Jul 2005
Posts: 37
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1 cylinder = how many tracks?
1 track = how many Giga / Mega / Kilo Bytes?
I am trying to perform tracks to cylinders conversion in mainframe. Want to know how many tracks in one cylinder and how many GB or MB or KB in one Track... |
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TizMe
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Joined: 05 Jan 2006
Posts: 72
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It depends on the DASD model used in mainframes.
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Model cyls byte/track byte/cyl byte/vol
3380-J 885 47476 712140 630MB
3380-E 1770 47476 712140 1.26GB
3380-K 2655 47476 712140 1.89GB
3390-1 1113 56664 849960 946MB
3390-2 2226 56664 849960 1.89GB
3390-3 3339 56664 849960 2.83GB
3390-9 10017 56664 849960 8.51GB
9345-1 1440 46456 696840 1.0GB
9345-2 2156 46456 696840 1.5GB |
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muppasani
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Joined: 03 Jan 2006
Posts: 4
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1 Track = 48 KB
1 Cylinder = 720 KB
so 1 Cylinder = 15 Tracks
Cylinder: A cylinder in a DASD consists of all the tracks that are aligned vertically across all platters at a given position of the read/write heads.
Track: Each cylinder contains a certain number of tracks, which corresponds to the number of recording surfaces (heads) in the DASD.
Regarding the storage capacity in gigabytes (GB), it depends on the number of bytes each track can store, which can vary based on the DASD model and configuration. For precise calculations, detailed specifications of the DASD model in use are required. |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19243
Location: Inside the Matrix
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Hello muppasani,
Please look at the table posted just before your posts and explain why your numbers are different than the table presented  Also, please note that there multiple models of 3390 DASD.
A 3390-n device has a capacity of 56,664 bytes per track,of which 55,996 bytes are accessible by applications programmers. And 1 cylinder is 15 tracks.
So let us take the accessible bytes in a track which is 55,996.
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1 Cylinder = 55,996 * 15 = 839,940 bytes.
so 1000 cylinders = 839,940 * 1000
1 Megabyte = 1,048,576 (2 to the 20th power) bytes.
1000 cylinders = (839,940 * 1000 ) / 1,048,576 = 801.029 MB
1 terabyte = 2 to the 40th power or approximately a thousand billion bytes (that is, a thousand gigabytes).
1000 cylinders = (839,940 * 1000 ) / (1,048,576 * 1,048,576 ) = .000763 Terabytes |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19243
Location: Inside the Matrix
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Hello,
While that was published, it is not complete (if is not even totally accurate). I suspect that there was some qualifying information in that publication - like these numbers apply to DB2 allocation, not all dataset allocation.
If you want to find the capacity for an IBM device and you don't want to search in these forums, i suggest looking to IBM as they "wrote the book" for "their" devices  |
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priya
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Joined: 24 Jul 2003
Posts: 568
Location: Bangalore
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Check this table for Disk Capacity:
/references/disk.html
I have an Excel software to find the no of tracks & cylinders for a particular DASD Model. Please find the attachment: |
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