Newsgroups: alt.sys.pdp10,alt.sys.pdp11,alt.folklore.computer Subject: Re: Ok, how many bytes make up a BLOCK in DEC-ese? References: <38851A6C.68784979@bellatlantic.net> Organization: Chez Inwap From: inwap@best.com (Joe Smith) Date: 19 Jan 2000 02:53:23 GMT In article <38851A6C.68784979@bellatlantic.net>, me wrote: >Is it the same across all OS's (RT, RSX, TOPS) or does it depend on that >and/or the disk media? A block is either 512 8-bit bytes (RT, RSX, VMS) or 512 9-bit bytes (TOPS). For the 36-bit operating systems (TOPS-10, TOPS-20 and variants) a block is 128 words. That translates to: 32 128-bit quad words (from cache to/from main memory) 64 72-bit doublewords 128 36-bit words 256 18-bit halfwords 384 12-bit PDP-8 compatible bytes (SAIL at Stanford used 12 bits) 512 9-bit bytes (control-shift-meta double cokebottle) 576 8-bit bytes (4.5 bytes per word, 9 bytes per two words) 640 7-bit bytes (regular text files) 768 SIXBIT bytes (used by COBOL) 1152 4-bit nybbles (FTP "image" mode) The SA-10 (and other IBM-compatible disk controllers) would read a pair of 36-bit words from the PDP-10's memory and write nine 8-bit bytes to the disk. The RH11 controller in the KS-2020 did I/O as 18-bit short words. The RP04 and RP06 disks had to be 18-bit formatted for the PDP-10 instead of the 16-bit format used by the PDP-11 and VAX. -Joe -- INWAP.COM is Joe Smith, Sally Smith and our cat Murdock. See http://www.inwap.com/ for PDP-10, "ReBoot", "Shadow Raiders"/"War Planets" From: Bill Westfield Newsgroups: alt.sys.pdp10,alt.sys.pdp11,alt.folklore.computer Subject: Re: Ok, how many bytes make up a BLOCK in DEC-ese? Date: 19 Jan 2000 00:54:21 -0800 Organization: Ye 'Ol Disorganized NNTPCache groupie Message-ID: <54vh4qo30i.fsf@flipper.cisco.com> References: <38851A6C.68784979@bellatlantic.net> <38852723$0$209@nntp1.ba.best.com> >> 512 9-bit bytes (control-shift-meta double cokebottle) The SAIL keyboards with the multitude of shift keys, and a separate bit for each one, generated 12 bit characters. Ctrl, Shift, Meta and Top, plus 8 bits for the key, I think. BillW -- (remove spam food from return address) From: alderson@netcom2.netcom.com (Richard M. Alderson III) Newsgroups: alt.sys.pdp10 Subject: Re: Ok, how many bytes make up a BLOCK in DEC-ese? Date: 19 Jan 2000 20:04:27 GMT Organization: NETCOM On-line services Message-ID: References: <38851A6C.68784979@bellatlantic.net> <38852723$0$209@nntp1.ba.best.com> In article Daniel Seagraves writes: >On 19 Jan 2000, Joe Smith wrote: >> 512 9-bit bytes (control-shift-meta double cokebottle) >What's cokebottle? From the Jargon File: COKEBOTTLE n. Any very unusual character. MIT people complain about the "control-meta-cokebottle" commands at SAIL, and SAIL people complain about the "altmode-altmode-cokebottle" commands at MIT. Both schools used experimental keyboards with additional graphics. For an example of one, see the character-set appendix in Knuth's _The TeXbook_. Rich Alderson Last LOTS Tops-20 Systems Programmer, 1984-1991 Current maintainer, MIT TECO EMACS (v. 170) Customer Advocacy, XKL LLC, 1993-now last name @ XKL dot COM Chief systems administrator, XKL LLC, 1998-now From: Mark Crispin Newsgroups: alt.sys.pdp10 Subject: Re: Ok, how many bytes make up a BLOCK in DEC-ese? Date: Wed, 19 Jan 2000 16:04:15 -0800 Organization: Networks & Distributed Computing Message-ID: References: <38851A6C.68784979@bellatlantic.net> <38852723$0$209@nntp1.ba.best.com> On 19 Jan 2000, Richard M. Alderson III wrote: > COKEBOTTLE n. Any very unusual character. MIT people complain about > the "control-meta-cokebottle" commands at SAIL, and SAIL people > complain about the "altmode-altmode-cokebottle" commands at MIT. Brian Harvey added that one, and I never heard anyone other than him use it. Not that there weren't other personal jargon items; most notable being QUUX (Guy Steele) and GAS (Geoff Goodfellow). -- Mark -- * RCW 19.190 notice: This email address is located in Washington State. * * Unsolicited commercial email may be billed $500 per message. * Science does not emerge from voting, party politics, or public debate. Path: news3.best.com!news2.best.com!news.maxwell.syr.edu!news.mindspring.net!firehose.mindspring.com!207.69.128.190!alderson From: alderson@netcom2.netcom.com (Richard M. Alderson III) Newsgroups: alt.sys.pdp10 Subject: Re: Ok, how many bytes make up a BLOCK in DEC-ese? Date: 19 Jan 2000 20:00:30 GMT Organization: NETCOM On-line services In article <38851A6C.68784979@bellatlantic.net> me writes: >Is it the same across all OS's (RT, RSX, TOPS) or does it depend on that >and/or the disk media? It differs by OS and media, as noted by others, but they're mostly Tops-10 folks. Tops-20 does not use the concept of "block" but rather of "page", which is defined as 512 *words* of 36 bits each. (NB: The *disk drivers* may use blocks, but they are not available to user- level programs, nor even to the rest of the monitor. On a SCSI disk, we format the disk into 2304-bit blocks (128 * 36 bits), four of which make up a page.) Rich Alderson Last LOTS Tops-20 Systems Programmer, 1984-1991 Current maintainer, MIT TECO EMACS (v. 170) Customer Advocacy, XKL LLC, 1993-now last name @ XKL dot COM Chief systems administrator, XKL LLC, 1998-now