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rfc:rfc180

Network Working Group Alex McKenzie Request for Comments #180 BBN NIC #7123 25 June 1971 Categories: D.7, G.3 Updates: none Obsoletes: none

                     File System Questionnaire

As noted in RFC #164 (page 35), a subcommittee of the NWG, under the chairmanship of Abhay Bhushan, is currently generating proposals for a "data transfer protocol" and a "file transfer protocol".

The subcommittee has decided that the file transfer protocol should provide standard methods for requesting the transfer of a file but should not, at this time, attempt to standardize file naming conventions, access control conventions, and the like. Thus a user who is, for example, trying to store a file on a remote Host will be required to use the file naming conventions appropriate to the remote Host.

Given the above point of view, it becomes imperative for users to have some source of information about Host file conventions. Such information, once compiled, will also serve as input to possible standardization efforts of the file transfer subcommittee. For this reason Abhay has asked me to solicit information on file conventions from the Host organizations. What follows is a description of the kinds of information of interest. I am well aware of the fact that many of you are tired of writing system descriptions; Xerox copies of short sections of your local documentation are fine if the result is complete and comprehensible. (In the case that your Host will never permit network use of your file system, a note to that effect would be sufficient.)

                       Information Requested

1. File naming conventions - We (loosely) define a pathname to be

  the data string which must be input to the file system by a user
  (a network user if your system makes a distinction between local
  and network users) in order to identify a file.  We are interested
  in syntax, semantics, and defaults.  Typical components of pathnames
  are:
  1. "device" fields
  2. user names
  3. version numbers
  4. index names
  5. punctuation marks
                                                              [Page 1]

Common types of defaults are:

  1. device is disk
  2. version number is largest in system
  For hierarchical file structures, descriptions may be fairly
  complex, but with lots of defaults; in such cases an illustration
  of a "normal" pathname might be helpful.

2. Access control mechanisms - Access control mechanisms range from

  simply knowledge of a file's pathname to elaborate hierarchies
  of group-project-task-username membership with passwords and
  separate controls for reading and writing.  There are two
  aspects of the access control mechanism which are of interest:
  a.  A description of what inputs the user should give the file
      system, both at the time of file creation and at the time of
      retrieval, in order to define the permitted modes of access
      and to gain access.  What are the syntax and semantics of
      these inputs?
  b.  A description of the ways in which the access control
      mechanism is designed to help (or hinder) the sharing of
      files.  For example, may two users "simultaniously" update a
      given file?  May the creator of the file define a set of
      authorized users to the file system (and how)?  Is it possible
      to define different access controls for various subunits of a
      given file?

3. Directories - Many systems maintain file directories which are

  designed to be helpful to the user.  A directory might, for
  example, provide a list of all files created by a particular
  individual, along with some information regarding file size,
  file structure, access controls, etc.  In general, such systems
  allow the user to input a pathname and retrieve the directory to
  which that pathname refers.  Aspects of the directory structure of
  interest are:
  a.  What are the syntax and semantics of a directory pathname?
  b.  What use is a directory, i.e., what type of information
      does the directory contain?
  c.  What access controls are used for access to the directories?
      For example, must a user supply a password in order to
      retrieve a directory, and is this password typically the same
      as the password he would use to retrieve a file listed in that
      directory.
                                                              [Page 2]

4. Commands and functions of the file system - A general description

  of what the file system is designed to do would be useful.  For
  example, the system might simply accept an entire file and store
  it sequentially on a tape; with the only mode of retrieval being
  to retrieve the entire file.  On the other hand, the system might
  provide the ability to access any "subfield" with a unique
  pathname.  Perhaps there is the ability to restructure a file,
  change the access control, delete all the fields associated with a
  directory, etc.  We realize that this aspect of the file system
  begins to overlap the area of "data management", which is the
  responsibility of another subcommittee; therefore, use your
  judgement as to what functions are an intrinsic aspect of the
  file-handling system and which are aspects of "data-management".

5. Internal representation and I/O modes - The remote user of a file

  system will normally be interested in internal representation of
  data only insofar as that representation of data is reflected in
  the I/O interface between the file system and the network.  For
  example, if all of the file system's I/O is in 8-bit ASCII
  characters, then the user is unlikely to care if they are stored
  in ASCII, EBCDIC, or some other form.  However, if an alternate
  transmission mode is available it may be useful; for example,
  two PDP-10's, both of which store 5 characters and one "filler"
  bit per word, might find it advantageous to transfer information
  in this mode rather than converting between internal representation
  and 8-bit ASCII for each character.  Other information on internal
  representation which would be of interest to the user might
  include (if applicable):
  1. range of numeric data permitted
  2. maximum text string lengths
  3. whether the user must indicate "record" boundaries on input
  4. what "logical structure" information the user may specify

for a new file, and what he must specify

  1. whether the user must specify the file size before beginning

input, and how he does it

6. Undoubtedly, there will be aspects of each file system which don't

  fit neatly into the categories above, but which users will find
  important or essantial in using the system.  These should be
  identified and described if possible.
  Please address responses to this questionnaire to:
             Alex McKenzie
             Bolt Beranek and Newman Inc.
             50 Moulton Street
             Cambridge, Massachusetts 02138
                                                              [Page 3]

If the questions above are confusing, don't hesitate to call me for clarification at (617) 491-1850 ext. 441. I will issue another RFC summarizing the responses after I have received a significant number of them.

     [ This RFC was put into machine readable form for entry ]
       [ into the online RFC archives by Stefan Hinker 6/97 ]
                                                              [Page 4]
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