Date: 2007-11-07 08:44:47
Hallo allemaal, @Jim: > You have heard of expansion part extenders, right? Of course I have, I don't live in Far-away-istan :) But FC3 doesn't like other cartridges parallel to itself. And I also have bad experiences with the switchable expanders. And to return the ball: I have heard of expanders for the Userports :) > Sellam wishes to have a cart he can plug into the machines so > they do not have to be booted by hand. Thus, they'll be a > cart there anyway. Nope, no cart needed. Somewhere in the '80s I saw an ingenious solution in a 64er magazine: replace the original ROM with a 27128 and connect A13 to the cassette port. The C64 starts up with the software in the upper part of the ROM, does what it has to do, copies a bit of ML into RAM and from there it negates A13 of the 27128 and does a "JMP ($FFFC)". Regarding this upper part, it could load more software from a drive and even better, it could tell the C64 to load its software from the network. In this case you only have to maintain the boot software at one place. And of course we are not limited to use a 27128 only. Replace it was a Flash tahta holds all the needed SW and when needed, it can update itself over the network. Regarding the automatic boot: using UTP we can reserve one line for telling the system that the network is alive by pulling it High. The first C64 to be started sees a (H) on this line and waits for its masters hand to tell it whether to start up the network or not by negating this line. All other C64's that are connected then see a (H) on this line and will automatically start the network software. You don't want to use a particular C64 on this net? Simply disconnect it. OK, it will assume that it is the first one on the net and thus awaits your input but that is a small price IMHO. Why (H) and not (L) you may wonder? I'm thinking of a system where this (H) powers a small electronic system that on its turn powers up all connected computers: a wake-up-on-LAN function I mentioned yesterday. The most simple thing that comes in my mind is a relay that switches the power supply for the C64 to "ON". > It seems a token passing or some other collision > avoidance scheme is needed. Using a token is the safest way but it also means that in one or another way the C64 has to watch the network all the time to be able to pass the token to the next C64. And if someone is running SW that disables the network SW in some way, the token passing is stopped and the whole network down. Using a master could solve this problem but that means an extra C64 doing "nothing". Only using up to, let's say, four computers, I would use collision detection, Just as David described. But using five or more computers I would start thinking of using a Master. @David: > The address could be encoded in hardware with dipswitches > on the userport parallel lines. Use a 74166 (I think), a parallel-to-serial converter. Only one clock and one input needed. Two 166's and you have up to 65536 addresses. And still only two lines needed. Would fit on the cassette port as well. KISS :) -- ___ / __|__ / / |_/ Groetjes, Ruud \ \__|_\ \___| URL: Ruud.C64.org De informatie in dit e-mailbericht is vertrouwelijk en uitsluitend bestemd voor de geadresseerde. Wanneer u dit bericht per abuis ontvangt, verzoeken wij u contact op te nemen met de afzender per kerende e-mail. Verder verzoeken wij u in dat geval dit e-mailbericht te vernietigen en de inhoud ervan aan niemand openbaar te maken. Wij aanvaarden geen aansprakelijkheid voor onjuiste, onvolledige dan wel ontijdige overbrenging van de inhoud van een verzonden e-mailbericht, noch voor daarbij overgebrachte virussen. Stichting Pensioenfonds ABP is gevestigd te Heerlen en ingeschreven bij de Kamer van Koophandel Zuid Limburg onder nummer: 41074000 The information contained in this e-mail is confidential and may be privileged. It may be read, copied and used only by the intended recipient. If you have received it in error, please contact the sender immediately by return e-mail; please delete in this case the e-mail and do not disclose its contents to any person. We don't accept liability for any errors, omissions, delays of receipt or viruses in the contents of this message which arise as a result of e-mail transmission. Stichting Pensioenfonds ABP, having its registered office at Heerlen, is registered in the Traderegister of the Chamber of Commerce Zuid Limburg (Maastricht), the Netherlands, registration number: 41074000 Message was sent through the cbm-hackers mailing list
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