From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: * X-Spam-Status: No, score=1.1 required=5.0 tests=BAYES_00,INVALID_MSGID, TO_NO_BRKTS_PCNT autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,485ea727233a52ce X-Google-Attributes: gid103376,public From: "Marin David Condic, 561.796.8997, M/S 731-93" Subject: Re: Will Boeing Use Ada To Build $9 Bln Network For Teledesic? Date: 1997/05/02 Message-ID: <97050216243711@psavax.pwfl.com>#1/1 X-Deja-AN: 239072527 Sender: Ada programming language Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU X-Vms-To: SMTP%"INFO-ADA@VM1.NODAK.EDU" Newsgroups: comp.lang.ada X-Vms-Cc: CONDIC Date: 1997-05-02T00:00:00+00:00 List-Id: Dale Pontius writes: > >Really, I suspect the 20% of weight they're talking of is, of >course storage media, be it RAM, ROM, or tape. But what may have >really happened here is that a threshold has been crossed. Perhaps >the storage technique that worked with less sophisticated (or >bloated?) software has become insufficient. Perhaps the issue is >no longer "more of the same" storage, but a new hierarchy or new >media. > It could also be a matter of "large" software demanding more compute power which can demand more or bigger (physically) processors. Increases in clock speeds can also translate into energy consumption (bigger heat sinks, etc.). It might be an issue of increasing the size/complexity of the software causing a whole redesign of the computer which increases the weight. >Is it possible to use a hard drive on a small satellite, or will >the rotating platters foul things up. I'd expect that the shuttle >is so big that the effect is insignificant. > When rockets fire, you get *lots* of vibration. Head crash on a disk drive on a satelite would be *very* bad! And don't forget that spinning a disk platter is going to consume electricity - moreso than an EEPROM (unless you had a *lot* of EEPROM!). It may be that somebody has figured out how to use a disk drive in this sort of application, but it wouldn't be my first choice. I'd be real curious to find out about any space-based embedded computers that used a disk drive in an unmanned vehicle. (I wouldn't be suprised if there were some in the shuttle, but that gets to come home rather quickly and breakage there may have less critical impact.) I doubt the rotation of a disk say the size of one in a notebook computer would significantly impact the course or attitude of a satelite - even a "small" one. (Even "small" satelites are pretty heavy in comparison to the weight of a notebook sized disk.) And most satelites I know of contain some ability to adjust their course & attitude in flight to compensate for drift from any & all sources. MDC Marin David Condic, Senior Computer Engineer ATT: 561.796.8997 Pratt & Whitney, GESP Fax: 561.796.4669 West Palm Beach, FL Internet: CONDICMA@PWFL.COM =============================================================================== "It's a small world, but I wouldn't want to have to paint it." -- Steven Wright ===============================================================================