Re: Bug in Random File Access

[James J Dempsey <jjd@alexander.bbn.com>]

>> Date: Wed, 9 Dec 87 16:30+0100
>> From: Juergen Krey <unido!gmdzi!LISPM-3!krey@UUNET.UU.NET>
>> Subject: Bug in Random File Access
>> To: slug@R20.UTEXAS.EDU
>> 
>> Hi, Folks !
>> 
>> The following bug concerns the Random Access File capability of Genera
>> 7.1 .  I tried to open a file in random access mode an another host with
>> the following code.  There are no hints in Manual 5, that my options to
>> opening a file are inconsistent.
>> 
>> 
>> (defun do-it (&optional (path "aid:>krey>network>atu_2.lisp"))
>>   (setq path (fs:parse-pathname path))
>>   (with-open-file (in  path :direction :input :direct t)
>>     (read-record in 0 10)))
>> 
>> I think I remember this working in Rel 6.x
>> 
   <stuff deleted>

>> Thanks for any help
>> Juergen Krey
>> 
>> 

I complained about this one when Release 7 first came out.  It doesn't
work because the whopper FILE-ACCESS-PATH-OPEN for
FONT-ENCAPSULATING-ACCESS-PATH-MIXIN tires to read the attribute list
of the file using FS:READ-ATTRIBUTE-LIST which causes an error on
direct streams.  I think this change was made for the new character
style stuff.

When I complained to Symbolics customer-reports, I got the very
unhelpful reply that "direct streams aren't supposed to work on
character files, you shouldn't be doing this."  It did work in Release
6.1. 

Since we had (and still have) software which depends on direct
streams on character files, we made a local fix which seems to work
fine here at BBN.  The fix first checks to see if the stream is a
direct stream and doesn't do a FS:READ-ATTRIBUTE-LIST if it is a
direct stream.

Since it is fairly large and contains Symbolics code, I'll send it to
you under separate cover.

		--Jim Dempsey--
		BBN Communications
		jjd@bbn.com