Classification: Confidential Than sounds suspiciously like a "channel" on the mainframe (pick your favorite protocol).
-----Original Message----- From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Grant Taylor Sent: Tuesday, August 1, 2023 9:42 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Mainframe Makers.... WAS: Ars Technica: The IBM mainframe: How it runs and why it survives [CAUTION: This Email is from outside the Organization. Unless you trust the sender, Don’t click links or open attachments as it may be a Phishing email, which can steal your Information and compromise your Computer.] On 8/1/23 7:20 PM, David Crayford wrote: > What’s the difference between between channelized I/O and a rack of > x86 servers connected to a SAN using fibre channel driven by high > speed HBAs? I don't know. My understanding is that Fibre Channel is an evolution of SCSI which is supposedly a somewhat intelligent controller wherein the OS asks said controller to fetch / store some data for it. As I understand it, the OS & main CPU aren't involved in the transfer beyond asking the controller to do the transfer on it's behalf. I'd have to reference documentation to see if / how much Direct Memory Access comes into play vs the CPU's involvement in the transfer to / from the controller. But between the controller and the back end drive, as I understand it, the CPU ins't involved. So I can't say that "a rack of x86 servers connected to a SAN using fibre channel" isn't using channelized I/O. I think in many ways they are. This is a place where minutia matters. Grnat. . . . ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ::DISCLAIMER:: ________________________________ The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. E-mail transmission is not guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or may contain viruses in transmission. The e mail and its contents (with or without referred errors) shall therefore not attach any liability on the originator or HCL or its affiliates. Views or opinions, if any, presented in this email are solely those of the author and may not necessarily reflect the views or opinions of HCL or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of authorized representative of HCL is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately. Before opening any email and/or attachments, please check them for viruses and other defects. ________________________________ ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
