TUHS

tuhs@tuhs.org

61 participants
6531 discussions

by jnc＠mercury.lcs.mit.edu

> From: Larry McVoy > Not once did I think about packing, the structs somehow just worked on > the machines I was working on. Maybe the TCP/IP guys knew about spacing > in the structs. Not really! Of the first 6 TCP/IP implementations: https://gunkies.org/wiki/TCP_and_IP_bake_offs only 1 was in C - and it was a relatively late one. The earliest ones were mostly in assembler (PDP-10 and PDP-11). Noel

3 months, 3 weeks

Re: Any UNIX With No C In Userland?

by jnc＠mercury.lcs.mit.edu

> There may have been a better way to do it CLR R0 BISB (R1)+, R0 SWAB R0 BISB (R1)+, R0 That saved one instruction over the previous one. Noel

3 months, 3 weeks

Re: Any UNIX With No C In Userland?

by jnc＠mercury.lcs.mit.edu

> From: Phil Budne > BUT, the basic TCP and IP protocols seem to have been created with a > general care that two byte fields should be aligned at multiples of two > bytes Yes, because dealing with a 16-bit field that spans two PDP-11 16-bit words is a pain (espcially because the PDP-11 does not have a 'load byte into register _without_ extending the sign bit into the high half' instruction). Do realize that in addition to the early TCP implementation, the _first_ TCP router (at that stage, TCP and IP were not separate protocols) was also a PDP-11 (albeit programmed in BCPL, not MACRO-11). I remember the extension being a real PITA. To load an un-aligned 16-bit quantity into R0, one would have had to do something like (assuming a pointer to the un-aligned 16-bit quantity was in R1): MOVB (R1)+, R0 SWAB R0 BIC #0377, R0 BISB (R1)+, R0 There may have been a better way to do it, but that's the best I can come up with now; I recall we had to do something like that. Yes, the 16-bit fields were 16-bit word aligned. Noel

3 months, 3 weeks

Re: DCJ-11 processor with 20k FPGA

by Jason Stevens

the code in the repo is for the FPGA, the processor that is strapped to the FPGA well it runs the real code. It's like the 'minimig' Amiga emulator platform, a real processor, and FPGA to do all the IO heavy lifting. So it's not 100% FPGA but you are executing code on a real processor so you aren't exactly full emulation either. And it doesn't cost a fortune, assuming you can find one of these ancient microprocessors. -----Original Message----- From: emanuel stiebler To: Jason Stevens; 'tuhs(a)tuhs.org' Sent: 3/5/25 2:50 PM Subject: Re: [TUHS] DCJ-11 processor with 20k FPGA On 2025-03-01 07:11, Jason Stevens via TUHS wrote: > I assume people have seen this? > > https://github.com/ryomuk/TangNanoDCJ11MEM/tree/main > > > It's capable of running Unix v1 & some limited amount of v6 among other > things. The FPGA in question the Tang Nano 20k is sub 30GBP delivered from > AliExpress. > > Kind of neat to combine a real processor with a simple FPGA implementation > of the hardware. I just had a look at it, but he doesn't show the code, which runs on the TangNano?

3 months, 3 weeks

Re: Any UNIX With No C In Userland?

by jnc＠mercury.lcs.mit.edu

> From: Rob Pike > The notion that the struct layout must correspond to the hardware > device's layout is about as non-portable as thinking can get. I'm confused; I thought device register layout is inherently about as non-portable a thing as one could have, generally. (Exceptions: 1) the device is basically a single chip, so interfaces on two machines might be essentially identical, if they use the same chip; 2) someone made a 68K card that plugged into a QBUS, so drivers on a PDP-11 and that 68K could be identical.) Or did you mean that one could somehow disassociate the struct layout and the details of the device (assuming it has addressable registers, as became common)? How (I'm missing it)? Noel

3 months, 3 weeks

Re: Any UNIX With No C In Userland?

by jnc＠mercury.lcs.mit.edu

> From: "G. Brandn Robinson" > C was a language for people who wanted to get that crap out of the way > so they could think about binary representations. Huh? Sometimes C gets in the way of doing that; see below. > From: Dan Cross > They did indicate that alignment makes sharing _binary_ data between > VAX and PDP-11 harder, but that's truerepresentation of other aspects of product > types as well. Alignment is just one aspect of low-level binary representation; there's also length (in bits), which is critically important in several problem domains; device registers have already been mentioned, but more below. > From: Peter Yardley > Problems I have with C as a systems language is there is no certainty > about representation of a structure in memory and hence when it is > written to disk. That's yet another one. The area I'm thinking of (and which I saw a lot of) is code to implement network protocols (and I'm fairly astounded that nobody else has mentioned this yet). One has to have _absolute_ control over how the bits are laid out in the packet (which of course might wind up in any one of countless other machine types) - which generally means how they are laid out in memory. The whole concept of C declarations is not rich enough to really deal with this properly. For each field in the header, one absolutely needs to be able to separately specify the syntax (e.g. size in bits) and semantics (unsigned integer, etc). And if you want the code to be portable, so that one set of sources will compile to working code on several different architctures, it gets worse. Device registers, already mentioned, often only have to run on one type of machine, but having protocol implementions run on a number of different machine types is really common. I came up with a way to do this, without _any_ #ifdefs (which I don't like, for a reason I won't get into) in most source files. Dealing with byte order issues was similarly dealt with (one can't deal with it just in types, really, without making the type specification, and the language, somewhat complicated). I know later C's got better about richer variable semantics and syntax selection than the circa 1985 ones I was working with, but I don't think it was ever made completely simple and orthogonal (e.g. 'signed/unsigned/boolean/etc char/short/long/quad/word/etc') as it should have been. Noel

3 months, 3 weeks

Any UNIX With No C In Userland?

by segaloco

Given that anything that obeys the ABI and has assembler entries to the kernel can request services, it seems to me it would be possible to stand up a user-land without C being present. Have any UNIXen ever done this after the advent of C? - Matt G.

3 months, 3 weeks

Language-lawyers' field day (was Any UNIX With No C In Userland?)

by Douglas McIlroy

> Everything that can possibly be represented in a machine > register with all bits clear shows up as an integral zero literal. > '\0' == 0 == nullptr == struct { } == union { } Well, some things. 0.0f and other floating-point zero constants are represented by all-zero words (of various sizes) and are not integral constants. NULL does not "show up as an integral zero literal". 0==NULL is true only because 0 can be converted to NULL. Getting really lawyerly, one can cook up any number of bizarre "things that can possibly be represented" by an all-zero word, for example (char[4]){0,0,0,0}, and have no representation as an integral constant. Only 3 of the 5 examples fit the description of possibly being represented by an all-zero word. struct{} and union{} are gnu extensions with size zero. Even if you accept them as C, they have no machine representation and cannot be cast to int. The null pointer makes the list only thanks to the weasel-word "possibly". Although 0 can be cast to the null pointer, the result of casting a null pointer to int depends on its unspecified machine representation. Zero, of course, is a good choice because it's easy to test for, and is easy to omit from virtual address spaces. Doug

3 months, 4 weeks

Having dickens of a time compiling gcc-4.4.7 on tru64 .

by babydr DBA James W. Laferriere

Hello Anyone interested in this silliness , I am just recently trying to reacquaint myself with this os . Which I had a decent passing knowledge of at one time . Not any real OS level or driver coding , But was least decently acquainted . Now on with the preliminaries ... Any good software items to update on this ol'thing that give me a better chance of completing this task , Greatly welcome . I have folowed , ths article which is a copy from (imo) several places , tho all of them are using a axp-Emulator . <https://gist.github.com/jamesy0ung/eeac82997ebeae92873d1f2844a14ac3> I am using (I'll admit) a REAL AlphaStation 200 (4/100) with 384MB main memory & three disks all are U160's 2x4G+1x72G , OS is installed on the 72G(now) & has a /home dir for users rather that the default location . See info & error during make of gcc . Those numbers for the allocation & total have been exactly the same accross many iterations of attempts in that exact file . # sizer -v HP Tru64 UNIX V5.1B (Rev. 2650); Sun Feb 23 19:43:32 AKST 2025 It is at patch level 008 . and had successfully compiled & installed all the prerequisites shown in the article mentioned above . It Seems the OS doesn't know how to access the swap properly . root@as200:/home/buildnfs/gcc-4.4.7# env PATH=/usr/local/bin:/sbin:/usr/sbin:/usr/bin:/usr/ccs/bin:/usr/bin/X11:/usr/dt/bin:~/bin:. make ... many lines snipped ... /home/buildnfs/gcc-4.4.7/host-alpha-dec-osf5.1b/prev-gcc/xgcc -B/home/buildnfs/gcc-4.4.7/host-alpha-dec-osf5.1b/prev-gcc/ -B/usr/local/alpha-dec-osf5.1b/bin/ -c -g -$ cc1: out of memory allocating 135816 bytes after a total of 796519376 bytes make[3]: *** [fold-const.o] Error 1 make[3]: Leaving directory `/home/buildnfs/gcc-4.4.7/host-alpha-dec-osf5.1b/gcc' make[2]: *** [all-stage2-gcc] Error 2 make[2]: Leaving directory `/home/buildnfs/gcc-4.4.7' make[1]: *** [stage2-bubble] Error 2 make[1]: Leaving directory `/home/buildnfs/gcc-4.4.7' make: *** [all] Error 2 # swapon -s Swap partition /dev/disk/dsk2g: Allocated space: 249774 pages (1.91GB) In-use space: 1520 pages ( 0%) Free space: 248254 pages ( 99%) Swap partition /dev/disk/dsk1b: Allocated space: 49152 pages (384MB) In-use space: 1630 pages ( 3%) Free space: 47522 pages ( 96%) Swap partition /dev/disk/dsk0b: Allocated space: 49152 pages (384MB) In-use space: 1618 pages ( 3%) Free space: 47534 pages ( 96%) Total swap allocation: Allocated space: 348078 pages (2.66GB) In-use space: 4768 pages ( 1%) Available space: 343310 pages ( 98%) # hwmgr show scsi SCSI DEVICE DEVICE DRIVER NUM DEVICE FIRST HWID: DEVICEID HOSTNAME TYPE SUBTYPE OWNER PATH FILE VALID PATH ------------------------------------------------------------------------- 42: 0 as200 cdrom none 0 1 cdrom0 [0/4/0] 43: 1 as200 disk none 2 1 dsk0 [1/0/0] 44: 2 as200 disk none 2 1 dsk1 [1/1/0] 45: 3 as200 disk none 2 1 dsk2 [1/2/0] # hwmgr -view dev HWID: Device Name Mfg Model Location ------------------------------------------------------------------------------ 3: /dev/dmapi/dmapi 4: /dev/scp_scsi 5: /dev/kevm 29: /dev/disk/floppy0c 3.5in floppy fdi0-unit-0 42: /dev/disk/cdrom0c TOSHIBA DVD-ROM SD-M1401 bus-0-targ-4-lun-0 43: /dev/disk/dsk0c IBM DDRS-34560D bus-1-targ-0-lun-0 44: /dev/disk/dsk1c COMPAQ BD07286224 bus-1-targ-1-lun-0 45: /dev/disk/dsk2c COMPAQ ST34371W bus-1-targ-2-lun-0 46: /dev/random 47: /dev/urandom Tia , JimL -- +---------------------------------------------------------------------+ | James W. Laferriere | System Techniques | Give me VMS | | Network & System Engineer | 3237 Holden Road | Give me Linux | | jiml(a)system-techniques.com | Fairbanks, AK. 99709 | only on AXP | +---------------------------------------------------------------------+

4 months

Re: Pre-Struct C Compiler with Funny Syntax Resurrected

by Douglas McIlroy

Yufeng, > I've recently brought the "prestruct-c" compiler back to "life" Great archeology! It seems you've unearthed a snapshot from the brief period when Dennis was struggling to reconcile byte addressing with BCPL pointers--the seminal innovation of C. In characteristic Unix fashion, he was trying out his ideas as they developed. I had forgotten that product types were under con-struct-ion at the same time. That really was a big bang. Doug

4 months, 1 week

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