From mboxrd@z Thu Jan 1 00:00:00 1970 From: jacob.ritorto@gmail.com (Jacob Ritorto) Date: Wed, 7 Jan 2015 08:29:11 -0500 Subject: [TUHS] pdp11 UNIX memory allocation. In-Reply-To: References: <54AC4394.3050302@update.uu.se> <1420576433.410248.210385277.513EF8EC@webmail.messagingengine.com> <5E62DDAA-0055-46FB-8077-92DB856DEEE0@ronnatalie.com> <2509FDBD-67C4-4552-BB58-01281049DCB6@ronnatalie.com> Message-ID: > > But why would you include an a.out header in a boot block? When you only > had 512 bytes, every one of 'em counted, and I, oops, I mean others, had > to resort to vile stuff such as self-modifying code... > > Ooh, can we see annotated examples? This is the really delicious stuff! > > I heard a story that on sufficiently-early Unices, the header was indeed > loaded, hence the "407". > Any grey-beards here like to comment? > +1 for hearing that and wanting to see annotated examples of it as well! On Wed, Jan 7, 2015 at 1:29 AM, Dave Horsfall wrote: > On Tue, 6 Jan 2015, Ronald Natalie wrote: > > > Yep, the only time this [the 407 magic number] was ever trully useful > > was so you could put an a.out directly into the boot block I think. > > But why would you include an a.out header in a boot block? When you only > had 512 bytes, every one of 'em counted, and I, oops, I mean others, had > to resort to vile stuff such as self-modifying code... > > > During normal operations the a.out header was never actually loaded into > > the user memory. > > I heard a story that on sufficiently-early Unices, the header was indeed > loaded, hence the "407". > > Any grey-beards here like to comment? > > -- > Dave Horsfall DTM (VK2KFU) "Bliss is a MacBook with a FreeBSD server." > http://www.horsfall.org/spam.html (and check the home page whilst you're > there) > _______________________________________________ > TUHS mailing list > TUHS at minnie.tuhs.org > https://minnie.tuhs.org/mailman/listinfo/tuhs > -------------- next part -------------- An HTML attachment was scrubbed... URL: