I think we should not relay to much on both the description and the
pictures.
It's only press article.
My understanding is the actuator is "partitioned", so each platter is
served by single head, but there are two actuators and - this is the
difference from 33xx drives - whole assembly is seen as single disk.
(of course I rely on the article and my quick review, I can be wrong)
--
Radoslaw Skorupka
Lodz, Poland
W dniu 2017-12-20 o 16:05, Joel C. Ewing pisze:
No, not the same.
>From the description of the physical characteristics of the 3380 & 3390,
it was clear that each actuator accessed independent platter surfaces.
The R/W heads on different actuators did not access the same physical
surface much less the same physical track.
The 3380 & 3390 hard drive modules each contained two functionally
independent hard drives within a single module. Putting platters for
both in one module housing reduced costs and size by allowing platters
for two drives to have a shared drive shaft, shared bearings, and a
shared drive motor.
The Seagate design description clearly indicates two R/W heads
accessing the same physical track. That sounds like they can at a
minimum be used to cut rotational latency time in half, and maybe (not
clear) even read or write different parts of the same track at the same
time with the potential for doing a full-track transfer in only 1/2
revolution of the disk. If both are true, they have effectively doubled
the peak transfer rate of the drive and cut the latency time in half
without having to increase either the density or rotational speed of the
device.
Joel C Ewing
On 12/20/2017 07:31 AM, Vernooij, Kees (ITOPT1) - KLM wrote:
The 3380 (3390 also?) had the same, one pack of disks with 2 independent
actuators on each side, representing 2 volumes.
Kees.
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On
Behalf Of Tony Thigpen
Sent: 20 December, 2017 14:19
To: [email protected]
Subject: Re: Can anyone remember "drum" storage?
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.
http://www.theregister.co.uk/2017/12/19/seagate_disk_drive_multi_actuato
r/
[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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