test-drb

test-drb@ccmp.vtda.org

101090 discussions

You've got to be pulling my chain... (Ethernet)

by allisonp＠world.std.com

<The PDP11 (at least every PDP11 that I've used) addresses memory by <bytes. OK, a 16 bit word, like an instruction, does have to lie on at an <even address, but the 16 bit address that a program generates (before <translation by the MMU) addresses one of 64K _bytes_ True but, if the memory contained nothig but instructions and addresses 32KW is the limit. Only data or IO is addressed as bytes. This would seem a trivial item it makes a difference in terms of the total number of instructions in any given amount of ram. This is more important when applied to machines with I&D space where the byte addressability can be exploited for buffers and the like. <The I/O page (certainly on Unibus PDP11's) is 4 K _words_ long. Without <an MMU you have 28kW memory, 4kW I/O Some versions and OS vaiations allowed a 2KW IO space. I've run RT-11 that way. <Wit hthe MMU enabled you can have 64k Bytes (32 k Words) of memory mapped <in. In fact you generally don't map the I/O page into user processes, <since you don't want user processes accessing device registers. True but then people ahve to understand that the MMU design seperates user space from system space. <Even if you have the MMU it's a lot simpler if your program fits into 32 <kW (or 28kW if you want access to the I/O space). Otherwise you have to <do something like using a software interrupt to change the MMU to a <different mode. I tried to keep it simple. <Unless page K1-11 of my PDP11/44 printset is wrong, the PDP11/44 has 22 b <addressing. The PDP11/45 does, indeed, only have 18 bit, alas... With the exception of the 11/70 I thought most of the unibus machines were limited to 18bits, for some devices that can be a limit. My interaction with U-bus machines is limited to the 11/70 and a 11/34 all my PDP11 time is with Q-bus (11/03, falcon, 11/23, 11/23A, 11/23b, 11/73) which has sufficient enough variation to track. Allison

28 years, 4 months

You've got to be pulling my chain... (Ethernet)

by allisonp＠world.std.com

< Allison, this was private email, but I figure this may be OOPs, though I did check the header as classiccmp...? < like the 11/23 and 11/73 line should run this BSD variant as < well... what I want to know is, did the kernel fit into 64K in < one segment, or did they spread the kernel across segment < bounderies? If so, how? The kernel never fit in 64kb as the pdp11 is word addressed also the MMU operates on 4kb pages. Also the top 4kbytes are IO space. So the idea of the kernel fitting in 64k is not relevent. The real question was did it fit in the 11/44 or 45 who only had 256k (18bit addresses) space. The 11/23 and later Qbus machines were Q22 (4mb address space). The larger space means more available ram that can be used without resorting to swapping (or at least less frequently). Also PDP11s come in two other flavors, those with I&D space and those without. The 11/23 and 11/34 are those without. The 44, 45, 70, 73, 83 and others have I&D which means that Instructions and Data spaces can be seperate doubling the amount of memory available. Added to that is user and system space (memory protection between processes). So it's possible for a PDP11 to actaully address four distinct areas of memory that are non-overlapping and all 64k in size. Practical considerations limit it to less than that but it's nearly so and likely they would overlap as well. < I mean, I could see overlays (in the kernel... blech!), but I < don't remember the 11 supporting long long jumps... and address < value was 16 bits, period. Still, I was never great at 11 True of all segmented address machines. The larger 256k or 4mb space is broken into pages of which up to 8 are mapped into the 16bit address space. To do a long jump what is really done is the cpu remapped the needed page into logical space and does a 16bit jump to that page. The top 4 bits determine what page register is addressed and the contents of that register is appended to the lower 12 bit to form the larger address needed to manage a 4mb space. It takes 8 MMU registers and uses the content of the reg plus the 16bit address to form an address in physical space. < assembly. Could someone here give a good detailed account of < PDP-11 segment mapping support? Could my stack and register < values be retained and follow while moving from segment to < segment? And how the hell did you tell the memory manager you < wanted to pop to another segment, anyway? yes! A detailed discussion would wear out my fingers typing it. Sufficient that it was able to address more than 64k and while different than the 8088 or 286 in both cases the 16 bit address space was extended by argumenting the basic addressing and not extending the basic register set. I'm currently building a system using the z80 cousin called the z280 that can address 16mb of ram and the basic addressing is still 64k argumented by a MMU. Allison

28 years, 4 months

You've got to be pulling my chain... (Ethernet)

by peacock＠simconv.com

> I seem to remember early Ethernet interface VAX quad cards > being around 1.5Mbps... not sure if it was think ether, vampire > tap stuff... This would have been before ethernet was turned > into a 'standard.' One guy I know has one of these hanging That is a DMC-11. It was an early networking card before Ethernet. It was point to point, 4 wire coax, synchronous serial at something around 1.5Mbps. The DMC-11 had an onboard bit slice processor (might have been a Signetics 8X305, not sure) to handle the packet assembly/disassembly. BTW the KMC-11 was a generic DMC-11 that was user programmable, if you wanted to roll your own protocols. I used a pair of DMC-11s in 1977 to network two PDP-11/34s with an early version of DECnet. I don't recall that DEC had any multi-drop type network interface at that time, except maybe for X.25 PADs.

28 years, 4 months

You've got to be pulling my chain... (Ethernet)

by allisonp＠world.std.com

< Alright, so what we have is the last 4KW used up for stack < space, register mapping, and IO mapping. I would guess the and also boot proms. Default boot on PDP11 is 173000Q. The first page is where all the vectors for the interrupts and traps are. < MMU... do I have it right? Even on a machine with a full < 22bits of address lines on the backplane, like an 11/73, the < CPU still only has a 16bit address space. The faq doesn't make < it terribly clear what happens if you want to open up any < arbitrary window. Think of the 4mb (q22) as linear physical space. At any time the CPU/MMU can allocate contigious or scattered blocks of that space as logical physical space. To do a "long jump" a local jump to a system space is done, memory management code is run and then a jump to the now available code (in logical space) is done. One of the background jobs would be to swap out old segments that are unused to make room for current processes and swap them back if the non current process should wake up. The cpu is always in logical 16bit space but the windows (multiple) can be moved around. An ascii graphic would show the CPU 16bit space as several blocks mapped to multiple blocks scattered in a larger space. The cpu literally never leaves the range of a 16bit space but instead trade out chunks of it for different ones out of an available pool. You never actually jump put of logical space only shuffle what physical memory is part of that space. Allison

28 years, 4 months

Asshole

by SUPRDAVE＠aol.com

who bloody cares?! people, deal with your own problems; I dont want to hear about them on the list. I have enough to deal with myself! david, back to deleting stupid messages <again> In a message dated 98-04-10 17:47:45 EDT, you write: << Without comment enrico Anonymous wrote: > > Are you a fucking idiot, Limey? Cut the damn crying on the mailing list or you might just open a message one day and have your whole machine become instantly erased...Not a threat, a promise. -- ======================================================== Enrico Tedeschi, 54 Easthill Drive, Brighton BN41 2FD, UK Tel/fax(+01273) 701650 (24 hours) and 0498 692465 (mobile) please visit my website at: <http://www.brighton-uk.com> ========================================================

28 years, 4 months

gcc for VAX VMS

by pete＠dunnington.u-net.com

On Apr 10, 21:13, Zane H. Healy wrote: > Subject: gcc for VAX VMS > This touches on yesterdays VS2000 discusion. Somehow I got lucky today and > found a pointer to a VAX version of gcc at > ftp://ftp.cco.caltech.edu/pub/rankin/ of course I'm still trying to find a > VAX VMS version of tar and gzip so I can install it. Take a look at http://www.openvms.digital.com/openvms/freeware/cd.html Near the bottom of the page you'll find the "Tools" section, which includes zip, unzip, gzip, and vmstar. Unzip, gunzip, and vms tar are also on Digital's ftp site. There's a pointer at http://www.digital.com/info/vms-freeware.html or ftp directly from ftp://ftp.digital.com/pub/VMS/vmstar-vax.exe Now, can someone remind me of the URL for VMS hobby licensing so I can do something about my MicroVAX? -- Pete Peter Turnbull Dept. of Computer Science University of York

28 years, 4 months

weekend additions

by SUPRDAVE＠aol.com

now, back to something on topic... picked up an unenhanced //e system for $10. a bit dirty from no use and a broken shift key, but powers up fine. came with 2 floppies, monchrome display which needs the contrast control cleaned and the ever popular system saver. this one has a hayes micromodem //e whereas the ][+ i got last week had a micromodem II. besides the way they connect to the phone line, are there any major differences? i presume both are still 300bps. david

28 years, 4 months

You've got to be pulling my chain... (Ethernet)

by pete＠dunnington.u-net.com

On Apr 11, 14:11, J. Maynard Gelinas wrote: > Alright, so what we have is the last 4KW used up for stack > space, register mapping, and IO mapping. I would guess the > first 4KW were used up by the boot prom and monitor, which > leaves about 12KW for an application jump table and > initialization, the rest for memory mapped windows to the > MMU... do I have it right? I'm not sure how you did the arithmetic :-) 4KW (8KB) is used for the "I/O Page" which *includes* the boot PROMs. Stack can be anywhere. > QUOTE: > 0 000 000 001 ddd ddd -- JMP JuMP > > Loads the destination address into the PC, thus effecting an > unconditional jump. > Why is the jump destination address only six bits long? > Jeesh, I hope I'm not asking the obvious.... Because the DDD DDD specifies a register (1 of 8) and address mode (1 of 8) to use. So, you'll often see something like JMP @#0173000, which is represented in two words 000137,173000. In this example, the address mode is 3 (auto-increment deferred, deferred = indirect) and the register to use is R7, which is the PC. So it means "jump to the address given in the word the PC points to". In other words, that's how you code an absolute jump. The reason for the auto-increment is that that mode is the general way of getting immediate data, and in the general case you do need to increment the PC after the read (think about MOV R0, @#0173000, opcode 010037,173000 which stores R0 in 173000). -- Pete Peter Turnbull Dept. of Computer Science University of York

28 years, 4 months

Thoughts about a Classiccmp private newsgroup

by photze＠batelco.com.bh

Yeah, but could such a thing be done on Linux/UNIX OS's? I'm guessing that you would need a NT server... and I don't like NT servers. I actually had a NT and Linux server running on the exact same machine, at different times. NT was harder to handle, and had more crashes just when I needed it most, with many requests. Also, I had to reboot it 8 times to get it set up with my video card, but not other cards, altogether, it took 16 reboots, compared to 1 with Linux. My NT 5.0 beta is showing some signs of hope, but I'll need a lot more before trusting NT with a hobby list as important as this one. Just my 0.02 Tim D. Hotze -----Original Message----- From: Richard A. Cini <rcini(a)email.msn.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 11, 1998 4:29 PM Subject: Re: Thoughts about a Classiccmp private newsgroup >On Fri, 10 Apr 1998 09:49:03 -0700 (PDT), Sam Ismail <dastar(a)wco.com> wrote: > >On Fri, 10 Apr 1998, Richard A. Cini wrote: > >> Anyway, as part of my Microsoft beta testing, I belong to a small >group >> of "elite" testers. Called ClubWin!, we have a private administrative >> newsgroup that requires a login name and password. Having a ClassicCmp >> newsgroup would provide a threaded conversation capability. We could also >> hang an e-mail gateway off of the news server to provide e-mail messages >for >> those who can't or want to use a newsgroup. > > >>>Give us more details, Richard. > > Well, since I wasn't the one who implemented the news server, I'm only >guessing as to its implementation. You can probably hang a NNTP (news) >server off of any Internet-accessible server. The news server has its own IP >address. Bill Whitson could create one off of the ClassicCmp server at >UofWA, or anyone else here with a free IP address and the approval of the >bosses. You could then also provide an e-mail gateway the news server so >that those who want the newsgroup activity by e-mail can get it. > > Authentication is either anonymous or login required. Each of us is >given a login name and password (like rcini and 12345678), which will be >required to logon. From there, your newsreader takes over. > >Rich Cini/WUGNET > <nospam_rcini(a)msn.com> (remove nospam_ to use) > ClubWin! Charter Member (6) > MCP Windows 95/Windows Networking >============================================ > > > >

28 years, 4 months

gcc for VAX VMS

by emu＠ecubics.com

Hi Pete, ---------- > From: Pete Turnbull <pete(a)dunnington.u-net.com> > To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> > Subject: Re: gcc for VAX VMS > Date: Saturday, April 11, 1998 8:33 AM > > does DECUS do in other countries? There must be lots of peopel like us who > keep old 11s and VAXen running. probably they don't use VMS ... ;-)) but serious, i think they expanding this Hobbiist thing to other countries. one day .... cheers, emanuel

28 years, 4 months

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