When I started working in the field, 1979, they had a couple of 2305 devices attached to a 3033 processor. They used it for PLPA and COMMON paging devices if I remember correctly.
Mark Jacobs > Joel C. Ewing <mailto:jcew...@acm.org> > December 20, 2017 at 10:05 AM > 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:IBM-MAIN@LISTSERV.UA.EDU] On > >> Behalf Of Tony Thigpen > >> Sent: 20 December, 2017 14:19 > >> To: IBM-MAIN@LISTSERV.UA.EDU > >> 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 > <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] > >>> > >>> > >> ... > > > -- > Joel C. Ewing, Bentonville, AR jcew...@acm.org > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > Please be alert for any emails that may ask you for login information > or directs you to login via a link. If you believe this message is a > phish or aren't sure whether this message is trustworthy, please send > the original message as an attachment to 'phish...@timeinc.com'. > > Tony Thigpen <mailto:t...@vse2pdf.com> > December 20, 2017 at 8:18 AM > 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_actuator/ > <http://www.theregister.co.uk/2017/12/19/seagate_disk_drive_multi_actuator/> > > > > [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] > > > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > Please be alert for any emails that may ask you for login information > or directs you to login via a link. If you believe this message is a > phish or aren't sure whether this message is trustworthy, please send > the original message as an attachment to 'phish...@timeinc.com'. > > John McKown <mailto:john.archie.mck...@gmail.com> > December 20, 2017 at 8:08 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_actuator/ > <http://www.theregister.co.uk/2017/12/19/seagate_disk_drive_multi_actuator/> > > [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] > > > -- > I have a theory that it's impossible to prove anything, but I can't prove > it. > > Maranatha! <>< > John McKown > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > Please be alert for any emails that may ask you for login information > or directs you to login via a link. If you believe this message is a > phish or aren't sure whether this message is trustworthy, please send > the original message as an attachment to 'phish...@timeinc.com'. > -- Mark Jacobs Time Customer Service Global Technology Services The standard you walk past is the standard you accept. Lt. Gen. David Morrison ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
