retrieve the actual facsimile document, the recipient must use his facsimile terminal. An explanation of this dialogue is given below. [1) This is the same Login to the Facsimile terminal as in Section [2) The user types in the #L BBNE command to access MSG system at that site7 –Ieten receives a header listing of his unread messages. [3] The user gives the #R 12, #0 command requesting the retrieval and-printing of his facsimile message. The FAXSYS then types the header of the message and afs- r confirmation. I.. ‘ : i – e ‘ ‘… I~a ~ l ” ” – ” ‘usps holiday schedule by someone else 

83 1.14 [4] When confirmed by a <CR>, the text portion of the message is r~etrieved a’nd prin’ted on hi~s console. Simultaneously, by using the cross reference number in the text message header [CCA% ] retrieval of the facsimile document is initiated. (5] Here the #0 command takes its effect, and the facsimile document is reproduced. (6) Having retrieved his facsimile message, the user deletes the message, exits from MSG, and closes connections to the Data-Computer, DIALOGUE L<C_ > COMMENTS [I] * UCL FAX-MESSAGE SYSTEM VERSION X.04, YOUR NAME: PASSWORD:.* LOGIN O.K. YILMAZ <CR> ‘t5c”7… TYPE #H FOR HELP <-#L BBNE <CR> (2) Connect to MSG MSG — Version of 1 April Oct Kirstein at ISI’ <<FACSIMILE, PGS:1, ID= CCA% >> “DEMONSTRATION OF UCL FAXSYS Last Read: i4 Oct msgs, 7 disc pages <-#R 12, #0 (CR> (3] Retrieva] <<ID=CCA% >> Confirml (CR> “” Mail from ISIA rcvd at 15 Oct Date: i5-oct From: Kirstein at ISIA [r 4 ] To: Yilmaz at BBNE cc: Kirstein at ISIA Subject: <<FACSIMILE, PGS=I, ID: CCA% >> “DEMONSTRATION OF UCL FAXSYS *.

84 1.15 (TEXT MESSAGE) Retrieval of CCA% is in progress O.K. FAX Me3sage Printed I <-#D 2, #B<CR>(6) DELETING CCA% [Confirm] <CR> Fig. 4 Dialogue for retrieving facsimile Messages 3.5 Generation of Message Code Numbers Since the textual and facsimile information are stored on different Host computers, it is necessary to devise a aross-referencing mechanism, so that messages can be manipulated uniquely. This is achieved in the following way: During the Login procedure to a Tenex, FAXSYS obtains the time and dite of login, which haj the format : DAY – MONTH – YEAR, HOURS – MINUTES – SECONDS.e.g Oct , ] This information is rearranged to form a twelve digit number which is unique to the message being sent. For the example given above the code number becomes : In fact, this code serves two purposes. Firstly as a link between the two portions of a facsimile message, and secondly as an identifier to store the facsimile information on the Data-Computer. However, since the Data-Computer does not accept a number as the first chara7ter in file names, the above code is padded with “CCA%”, thus producing : CCA% This identifier is generated and added into the text message headers before transmisaion. Its use during the storage and retrieval of facsimile data ia discussed in the next section.

85 4 Sarmead Retrieval at CA 4 1 Introduction The Data-Computer [Ref. 3) is a large-scale data storage utility- offering data storage and management services to other computers on ARPANET. The system is intended to be used as a centratie facility for archiving data, for sharing data among the various network hosts, and providing inexpensive on-line storage. The Data-Computer is implemented on dedicated hardware. and co-prises a separate “computing system specialised for data management. Logically the system can be viewed as a “closed box” shared by multiple external processes, and accessed in a standard notation called “Data-Lanauage” (Ref 31. The system is provided with an Ampex Terabit store of 10”12 bits. While this is mainl7 used-for seismic data, it does contain software and hardware ideal for archival storage. Thus it is an excellent vehicle for our experiments. In a paper of this nature it is not possible to enumerate every aspect of the Data-Computer, and our use of its facilities. Therefore, The Tollowing sections are limited to a discussion of the general principles closely related to our application, and the details are kept to a minimum. In Section 4.2 we discuss the directory structures set up in the Data-Computer. Section 4.3 presents the introductory – concepts of file security and password organisation. Section 4.4 describes the dcta structures used for storing facsimile information. And finally in Section 4.5 we discuss the mechanism for ac,’essing the Data-Computer, and translation of user req,,ests into Vata-Zanguage. 4.2 Directory Structure All data, whether being transmitted to or from the Data-Computer, or stored within it, must be formally aescrtbed to the Data-Computer. These data descriptions are kept in the-data7-computer directory which has a tree structure as illusfrated in Fig. 5. The entries in this directory are called “nodes”, and only the bottom-most nodes of any branch can contain data descriptions. There are three kinds of directory nodes. These are: FILE: containing a description of the format in w-ich the data is stored within the Data-Computer.

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76 The User’s View of the System The user FAXSYS dialogues take place via the system console. A -se’t.of commands permit the user to interact with the user interface process. Input of a command causes this process to activate the associated segments to perform the required operation. Our earlier work on a similar implementation [Ref. 5) had shown the importance of shielding the user from any fragmentation, and providing him with an understandable and unified view of the system. Therefore, the user is informed about the progress of his requests, but he is in no way made conscious of the complex operations behind the scenes. Table 1 at the end of this paper shows a list of the FAXSYS commands currently available, their meanings, and Thecorresponding working parameters. Each command is formed by a “#” sign followed by the first letter of the most significant word in the command phrase. The user can input more than one command for simultaneous operations. For instance: #L ISI, #E (CR> I I command string would log the user to the MSG system at the Information Sciences Institute in Los AngeT-e, and Examine his most recent [unread] messages. If there is a lessage in this category then it will list the header information on the user console. Similarly a command string: I #R 29, #U 18, #0 <CR> I would retrieve the message 29, recover an unintentionally deleted message 18, output the message 29 text on the console and output its facsimile portion on the facsimile device. If and when a command string does not contain a permissible combination [sequence), an error message is printed on the user console giving the details of the conflict.

77 The User Dialogues Document Transmission: A typical user dialogue for transmitting a one page document is shown in Fig. 3. There follows a commentary on this dialogue. [1) Start Up: The facsimile system software resides on a floppy-disc. On start up, typing an “L” to the Monitor loads the system into the memory, Tnitialises FAXSYS and prints out the title and the current versifonnumber, and asks the user his name and password to perform the Login procedure. If the login is successful it prinds out the FAXSYS prompt characters “<-” and waits for a commain input. For the subsequent operations, this portion of the dialogue will not be repeated. (2) Help: If a #H <CR> is typed, a Help file is produced on the console, giving Tnformation on the use of FAXSYS commands. (3] Addressing: Following the #C <CR> command the user is asked to specify the addressees, and others to whom a carbon copy of this notification and short text message should be sent. The subject field chosen should be informative as this will be the first thing the recipients will see. The information given by the user up to this point constitutes the MSG header. He is then asked the number of pages of–tacsimile document he wishes to send and their size. [4) Document Feeding: At this point the facsimile document is inserted into the machine for scanning. While the text message is baing typed in, the scanned data is processed and stored on a floppy-disc.

78 1.9 (5) Message Composition: The FAXSYS provides

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six editing characters which may be used to correct errors during this period. These are: AA to delete the last character AW to delete the current line ^N to expunge the message ^R to type the current line As to type the entire message “D to end the text input. here -A means <CONTROL> and “A” keys pressed simultaneously etc. ^A and “W can be used repeatedly. N allows the deletion of the entire text for a fresh start. [6) Message Transmission: Here the user types in the command string #N, #T ISI <CR> to indicate the transmission of his message. Since the MSG system is used directly, its facilities for imme late, delayed or queued transmission are invoked, and the whole message is sent in one burst. Simultaneously, the facsimile data is released to a message POOL on the Data-Computer and addressees’ message vectors are updatedto contain a new entry pointing to the message in the pool. This is discussed further in Section 4. [7) Message Confirmation Before the message transmission starts, the user is asked whether or not he wishes to receive a confirmation message after delivery. This is an optional facility used for mimicking “Recorded Deliveryn. When enabled, following the retrieval of the facsimile message the sender receives an automatically generated text mesage giving the necessary details. The use of this facility is limited to the main recipients, those specified in the “TO:” field. An example of this is given in Section
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79 1.10 (8) Message Delivery: Quite distinct from message confirmation (7) [which implies successful message retrieval I the user is also assured that his message has been correctly dispatched. Some of these replies come directly from MSG system, and thus all of its options such as-non-delivery, queued delivery, etc., may arrive. Similarly, confirmation of successful transmission of facsimile data is generated by FAXSYS when the appropriate signals are received from the Data-Computer. I!l

80 l * DIALOGUE COMMEhTS L <CR> FAXSYS loaded * ewucl FAX-MESSAGE SYSTEM VERSION X.04 *” YOUR NAME: KIRSTEIN <CR> PASSWORD: <SECRET> ZCM? [1) I [ I [ FAXSYS Login Not echoed LOGIN O.K. *…TYPE #H FOR HELP [2)! [ User Guidance <-#C <CR> I Compose Message TO, <CR> [3)! [ Addressing CC: MCR>! [ Self copy SUBJECT: DEMONSTRATION OF UCL FAXSYS I NUMBER OF PAGES: I (CR)> L41 I Document PAGE SIZE: A4 <CRy! [ Feeding INSERT FAX DOCUMENTS AND TYPE YOUR MESSAGE.! TEXT MESSAGE [5)! [ this <-#N,#T ISI <CR> [6)! [ Message I Transmitted! TENEX IS O.K. I [ Net Status DATA-COMPUTER WILL BE DOWN BETWEEN! AND ON THURSDAY 6-NOV I From FAXSYS MESSAGE CONFIRMATION [Y or N); Y <CR> [7) 1 [ Recorded Delivery I DELIVERING MESSAGE… 8)! [ Confirmation YILMAZ AT BBNE… O.K. [ of text KIRSTEIN AT ISIA… O.K. I. FAX IS DELIVERED! [of Fax. I Note: Characters input by the user are underlined, and Carriage Returns are indicated by <CR>. Fig 3. Dialogue for Message Transmission

81 Fig 3(a). Facsimile Message Transmitted in Section FWd Fig 3(b). Facsimile Message Retrieved in Section 3.4.2

82 Dialogue for Facsimile Message Retrieval Since the text portion of a facsimile message is sent via the MSG system, it can be retrieved on any alphanumeric terminal-. Thus the recipient of a text message may access MSG on the Tenex which he uses for regular messages in the course of Fis work. The retrieval dialogue takes the form shown in Fig. 4. After Login [1), and invoking MSG [2] he is informed about a new entry in his message file. This information which is automatically printed on the user console contains three distinct areas. Referring to the Fig. 4, these are: [1) <Message Status><Message Number><Date><Sender> [2) <Message Type><Message Length><Cross Reference> [3) <Subject of the Message> Fields [(1 and [3) are generated by MSG system where [3) is an exact replica of the Subject field typed in by the sender [see Section The second field in the header is generated by FAXSYS during message composition [Section 3.4.1). This partofthe header indicates to the recipient which that the is message 1 page is associated long, and with is a stored facsimile at CCA with document the reference number Generation of t~it- code is discussed in Section 3.5. Still connected to MSG, the user may wish to see if there is any interesting text for him. He can call all the processing facilities for MSG to file, forward or delete his message as he desires.”towever, to
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