I know MSS only from IDCAMS/VSAM/DFSMS parameters, attributes and
restrictions.
I had hard time to find out what kind of datasets are not SMS-eligible,
etc.
The device itself I saw on some photo maybe 10 years later.
--
Radoslaw Skorupka
Lodz, Poland
W dniu 2017-12-20 o 15:21, PINION, RICHARD W. pisze:
Drifting slightly, ever see the IBM 3850 Mass Store device, or see it in action?
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf
Of Allan Staller
Sent: Wednesday, December 20, 2017 9:17 AM
To: [email protected]
Subject: Re: Can anyone remember "drum" storage?
[External Email]
"pseudo-drum" - STK4305. I remember it well <sigh>
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf
Of Joel C. Ewing
Sent: Wednesday, December 20, 2017 8:15 AM
To: [email protected]
Subject: Re: Can anyone remember "drum" storage?
I don't think so. Says each R/W head accesses same disk blocks, and there
would be zilch improvement in speed if they were simply seen by OS as two
independent disks. By electronically selecting which of the two heads to use
to read the track based on which sees the start of the desired block first, you
cut the rotational latency time in half. With a single R/W head the only way
to get the same reduction in latency delay would be to double the rotational
speed of the platter, which might cause greater problems.
J C Ewing
On 12/20/2017 07:18 AM, Tony Thigpen wrote:
From reading the description, it really just appears to the OS as two
drives in one housing.
Tony Thigpen
John McKown wrote on 12/20/2017 08:08 AM:
It's not really a drum, but it is getting closer. Of course, for true
speed, one should go SSD.
https://apac01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww
.theregister.co.uk%2F2017%2F12%2F19%2Fseagate_disk_drive_multi_actuat
or%2F&data=02%7C01%7Callan.staller%40HCL.COM%7C1e585afeeaf14753335808
d547b42536%7C189de737c93a4f5a8b686f4ca9941912%7C0%7C0%7C6364937614319
95373&sdata=7BNHk4Ci%2Fq8zLD%2BgBDHrtFQOcgyBXiT1kUg1nK3fD6I%3D&reserv
ed=0
[quote]
Seagate is increasing IO performance in disk drives by separating
read-write heads into two separate sets which can operate
independently and in parallel.
The heads are positioned at one end of actuator arms which rotate
around a post at their other end to move the heads across the platter
surfaces.
Thus, with an eight-platter drive, each read-write head is positioned
above the same cylindrical track on each platter and reads or writes
to and from the same disk blocks on each platter's surface.
[\quote]
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