 

 

 

        Appendix I   A Glossary of 
Terms 

 

doc id 

     A tumbler assigned to a document 
upon its  creation  which  
corresponds  to its virtual stream 
address. 

doc-range 

     A virtual stream region 
containing several documents  defined 
by a span.  A doc-range is like a 
span, except that it specifies a 
"span" of documents rather than a 
span of text or links within a 
document.  Like  a  span,  it  
consists  of  a stream address and a 
width. 

end-set 

     Any of an indefinite number of 
terminii (defined by  tumbler  
addresses) a link may have on the 
virtual stream.  Examples include 
from-sets and to-sets, formally 
equivalent specifications 
distinguished only by  the  
directionality  desired and  
implemented  by their creator.  The 
creator is not neccesarily the 
"owner" of  the  document in 
question. 

from-set 

     The specification of the 
endpoint of a link from which  the  
link  was initially defined.  In the 
present minimal frontend  the  
position  of a from-set in the 
display of the document is indicated 
by reverse video text. 

link id 

     A tumbler assigned to a link 
upon  its  creation which corresponds 
to its virtual stream address. 

home-set 

     The specification of the 
document or spans  with which  the  
link is stored; an indication of the 
creator of the link.  The home-set of 
a link is not  necessarily  the same 
as that of either its from-set or its 
to-set. 

span 

     A pair of tumblers, a  starting  
stream  address and a width, that 
define a region of the virtual 
stream.  A span has two parts: a 
stream address and a width.  A span 
can describe any contiguous region of 
the virtual  stream.  Typically, the 
only instance of a span being used 
outside of a v-spec is in a 
doc-range. 

span set 

     A list of spans.  In the current 
implementation span  set  starts with 
an integer indicating the size of the 
set, followed by a string of spans. 

spec set 

     A list of doc-range and vspecs.  
The most common form  of  address  
specification that the system 
requests accept is the  "spec  set,"  
short  for specification   set.   In  
the  backend/frontend interface, a 
spec set  starts  with  an  integer 
indicating  the number of specs in 
the spec set, followed by a string of 
specs. 

spec 

     Either a doc-range or vspec.  A 
spec consists of a document id or 
link id, and a span set.  All spans 
in the span set refer to the document 
or link in the spec. 

stream address 

     A tumbler which corresponds to 
an address in the virtual stream. 

to-set 

     The specification of the 
endpoint of a  link  to which  the  
link  was initially created.  In the 
present minimal frontend the position 
of  a  to-set  in  the  displayed 
document is indicated by underlining. 

tumbler 

     The type of ordinal number used  
in  the  system for stream addresses. 
See appendix 2. 

virtual stream 

     All the data  on  the  system  
--  text,  links, etc.-- conceived as 
one extended list of bytes. 

virtual stream address or vsa 

     position of the thing -- 
document, link or character -- on the 
virtual stream. 

v-span set 

     A span set within a v-spec.  A  
v-span  set  can only  describe  
spans  within the document of the 
v-spec. 

v-span 

     A v-span has two parts, like a  
span:  a  stream address, and a 
width.  The stream address is not the 
entire tumbler address of the span in 
question, but only  the part which is 
local to the document or link.  For 
example, if the stream address is  
the first character of a document 
where the full address would be, say, 
17.0.23.0.42.0.1.1,  the  span's  
stream address would be simply 1.1, 
the rest is  already  known from the 
context of the spec.  The width is 
also a tumbler.  If you want to 
retrieve 500  characters,  the  width 
would be 0.500; if you wanted the 
entire text of the document, the 
width would be 1.  This is because 
the span's width added to the stream 
address is the address of  the  first 
thing  NOT  to  include.  Starting at 
1.1 with a width of 0.500 means that 
everything up  to  and not  including 
1.501 is specified.  With a width of 
1, the first non-included item would 
be  2.1, the first link. 

v-spec 

     A doc id followed by a spanset 

width 

     the size of a region; the sum of 
the origin  and width address is the 
first thing past the end of the 
region. 
