送信者: Tetsuro Kondo 宛先: Alan R. Whitney Cc: Wayne Cannon ; Brent Carlson ; Dick Ferris ; Dave Graham ; Nori Kawaguchi ; Sergei Pogrebenko ; Misha Popov ; Jon Romney ; Ralph Spencer ; Alan Whitney ; Ed Himwich ; Ari Mujunen ; JUNICHI NAKAJIMA 件名 : Re: VSI-S draft 2 日時 : 2001年4月3日 10:19 Dear Whitney-san and Gentlemen, Japanese group comments compiled by Nakajima-san regarding VSI-S draft 2 are asfollows. Best regards, Tetsuro Kondo ------ Dear Coordinator, Alan Whitney-san, > 5.1 Packet Structure > Each communication to/from the DTS is an elementary packet of the form: > Japanese group are perplexed with the modified VSI-S Version 2.0. Especially at the point of the packet structure cited above. The VSI-S control sequence is established on reliable ethernet or RS-232, and already they has own error correction mechanism. Our intention to establish the VSI-S is pursue a sophisticated scientific instrument control procedure beyond trifling hardware difference. 1) We would not like to accept any special character before or after VSI-S original command. 2) We can not accept to introduce any checksum with the command 3) We agree the merit of the sequence code. But, if one need the sequence code, it should be a sequential integer as well as unix process id. If one wish to introduce the check sum and invisible headers, They need explain the reason with occurring error rate in the RS/ether control communication line. Our laboratory are originally experts of "communications" and no one had taken such a way in the reliable internet control. Other High-Energy Physics group and Remote Sensing groups are interested in the VSI. It will be disadvantage of the VSI which will take such old-type, backward command structure. Our reccommendation is the original simple form. [] Japanese groups are already introduced real hardware and software. Especially NAO group is impossible to additional farm-ware to all existing instruments. We made up our mind to change them if the new idea to the VSI-S is inovative. But this is not the one. Regarding the VSI-H, we had introduced the proposed LVDS and TVG patiently. We will see whether the other groups really need connection between VLBI systems or just they want to move ahead sole idea. Best Regards, Junichi Nakajima$B!!(Bnakaji@crl.go.jp "Communications" Research Laboratory, CRL,KSRC, Radio Astronomy Applications 34m Radio Telescope VLBI Group$B!!(B +81-299-84-7145$B!!(B+81-299-84-7159