Inter-Office MemorandumToCommunication ProtocolsDateSeptember 10, 1982FromEd TaftLocationPARC/CSLSubjectLookupFile ProtocolFile[Maxc]LookupFile.bravoXEROX Attributes:informal, technical, communication, filingAbstract:The existence of a file, along with its create date and length hint, may be determined by a single exchangeof packets with a LookupFile server.The existence of a file, along with its create date and length hint, may be determined by a singleexchange of packets with the LookupFile server. This is intended to provide a means of filevalidation much cheaper than either FTP or Leaf. Its principal intended application is the CIFS filecache manager in Cedar.The server resides on socket 61B of any file server that offers this service. The client initiates theexchange with:LookupFileRequest:Pup type: 200BPup ID: chosen by clientPup contents: a text string identifying the fileIf the server is not offering this service, it responds with an Error Pup with sub-type 2, no suchport''. Otherwise, it responds with one of:LookupFileReply:Pup type: 201BPup ID: same as LookupFileRequest PupPup contents: 3 words, as follows:file version number (1 word)file create date, in standard Alto packed format (2 words, high-order word firstnotethat this is the reverse of the word order for a Mesa LONG CARDINAL)file length in 8-bit bytes (2 words, high-order word first)note that this is only ahint, and doesn't include the leader page.LookupFileError:Pup type: 202BPup ID: same as LookupFileRequest PupPup contents: 1-word error code whose interpretation is server-dependentIt is the client's responsibility to choose Pup IDs in such a way that it can correctly match responseswith requests.]gpi c8q]rX-q3r \q]r-q3r VDq]r-q3Osr Lq (F* J(M H$ CrR AI @N > ;qrG :' 7B51trq3 tr1t r# .*G ,,)'trq%tr#t r!}kU6q rTR*m\trqKtr:t r; UW   >Q\xLookupFile Protocol2This protocol is currently implemented by IFS file servers running version 1.36.4 or newer of theIFS software.The IFS implementation requires that the LookupFileRequest contain a complete IFS filename inthe form subdirectories>..>name!version'', except that the version may be one of thespecial version designators (!H'' or !L''), or may be omitted altogether in which case "!H" isassumed. Patterns containing *'' are not permitted.The error codes returned by IFS LookupFile servers are IFS internal error codes, whoseinterpretation may be found in file IFS.errors on that server. frXG b] ` ](5 \1V ZA! Y)6 VD; TFt Ty>QJ TIMESROMAN  TIMESROMAN TIMESROMAN LOGO TIMESROMAN j/  WLookupFile.bravoTaft.PASeptember 10, 1982 9:41 AM