From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timothy Sample Subject: Punch cards (was Preparing the reduced bootstrap tarballs) Date: Tue, 20 Nov 2018 10:28:10 -0500 Message-ID: <87zhu34vlh.fsf_-_@ngyro.com> References: <877eh81tm4.fsf@ITSx01.pdp10.guru> <87sgzw885x.fsf@elephly.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:34209) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gP7wq-0003nu-1b for guix-devel@gnu.org; Tue, 20 Nov 2018 10:28:20 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gP7wm-00050n-21 for guix-devel@gnu.org; Tue, 20 Nov 2018 10:28:20 -0500 Received: from wout2-smtp.messagingengine.com ([64.147.123.25]:38987) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gP7wl-0004yA-MU for guix-devel@gnu.org; Tue, 20 Nov 2018 10:28:15 -0500 In-Reply-To: <87sgzw885x.fsf@elephly.net> (Ricardo Wurmus's message of "Tue, 20 Nov 2018 09:28:26 +0100") List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: "Guix-devel" To: Ricardo Wurmus Cc: guix-devel@gnu.org, jeremiah@pdp10.guru Hi, Ricardo Wurmus writes: > jeremiah@pdp10.guru writes: > >>> for the lazyer like me, what about a punched card? :-) >> If someone is willing to figure out how to read a deck of punched cards >> without software, I'd be interested in learning more. > > Now that=E2=80=99s a project for a free hardware design that I=E2=80=99d = happily work > on :) > > Reading and transmitting of the bitstream can be done in hardware alone > (shift register, MUX, photoresistors, =E2=80=A6), though I=E2=80=99d need= to know what > kind of interface there is on the receiving side. Just flash memory / > TTL shift register? I=E2=80=99ve thought about this a bit. Would it be possible to go even more mechanical, and implement the SPI protocol in switches toggled by holes cut in some kind of insulating tape? You could have a couple of steel balls (bearings?) balanced on top of each other, connected to a circuit using brushes or springs. Then, you place the tape in between the bearings. When there=E2=80=99s a hole in the insulating tape, they make contact, and when there is no hole, no contact. Then, you have a row of holes for the SPI clock, and a row of holes for the SPI data. All you would have to do is hook up the right voltage to it, and you could write to a flash ROM by pulling manually punched tape through it. (You could use a crank or motor if the timing needs to be more precise.) Then, you could take an x200 and setup the bootrom to be whatever you wanted with no software whatsoever. If you adjusted stage0 to set up a =E2=80=9Ccache-as-RAM=E2=80=9D environment (like they do in coreboot), you = could do quite a bit of manoeuvring before having to initialize RAM. That is, you could probably set up a tiny Scheme environment and do more hardware initialization from there. Obviously all of this would be easier on a simpler computer, but then presumably you have to move from a simpler computer to a more complicated computer at some point (depending on your needs). The nice thing about booting the x200 as a simple computer is that you can just expand its boundaries until it is full-featured. Sorry for derailing a bit, I just wanted to share some idle thoughts. > -- > Ricardo -- Tim