diff --git a/aspinterface.c b/aspinterface.c
index 19915eb..b52b03d 100644
--- a/aspinterface.c
+++ b/aspinterface.c
@@ -12,7 +12,17 @@
 #include "asmglue.h"
 #include "cmdproc.h"
 
-static void CompleteCommand(Session *sess, Word result);
+typedef struct FPReadRec {
+    Word CommandCode;   /* includes pad byte */
+    Word OForkRefNum;
+    LongWord Offset;
+    LongWord ReqCount;
+    Byte NewLineMask;
+    Byte NewLineChar;
+} FPReadRec;
+
+#define kFPRead 27
+
 static void EndSession(Session *sess, Boolean callAttnRoutine);
 
 static void DoSPGetStatus(Session *sess, ASPGetStatusRec *commandRec);
@@ -40,7 +50,7 @@ void DispatchASPCommand(SPCommandRec *commandRec) {
                 break;
         }
         if (i == MAX_SESSIONS) {
-            CompleteCommand(sess, aspTooManySessions);
+            CompleteASPCommand(sess, aspTooManySessions);
             goto ret;
         }
         sess = &sessionTbl[i];
@@ -67,7 +77,7 @@ void DispatchASPCommand(SPCommandRec *commandRec) {
     // one is in progress
     if (commandRec->command != aspCloseSessionCommand) {
         if (sess->commandPending) {
-            CompleteCommand(sess, aspSessNumErr);
+            CompleteASPCommand(sess, aspSessNumErr);
             goto ret;
         }
         sess->commandPending = TRUE;
@@ -157,6 +167,37 @@ static void DoSPCommand(Session *sess, ASPCommandRec *commandRec) {
     sess->replyBuf = (void*)(commandRec->replyBufferAddr & 0x00FFFFFF);
     sess->replyBufLen = commandRec->replyBufferLen;
     
+    /*
+     * If the client is requesting to read more data than will fit in its
+     * buffer, change the request to ask for only the amount that will fit.
+     * 
+     * This is necessary because ASP request and reply bodies are limited
+     * to a "quantum size" of 4624 bytes. Even if more data than that is
+     * requested, only that amount will be returned in a single reply.
+     * If the full read count requested is larger, it simply serves as a
+     * hint about the total amount that will be read across a series of
+     * FPRead requests.  The AppleShare FST relies on this behavior and
+     * only specifies a buffer size of 4624 bytes for such requests.
+     *
+     * DSI does not have this "quantum size" limitation, so the full
+     * requested amount would be returned but then not fit in the buffer.
+     * To avoid this, we modify the request to ask only for the amount of
+     * data that will fit in the buffer.  This removes the function of
+     * hinting about the total read size, but should work OK in practice.
+     *
+     * A similar issue could arise with FPEnumerate requests, but it
+     * actually doesn't in the case of the requests generated by the
+     * AppleShare FST, so we don't try to address them for now.
+     */
+    if (commandRec->cmdBlkLength == sizeof(FPReadRec)
+        && ((FPReadRec*)commandRec->cmdBlkAddr)->CommandCode == kFPRead
+        && ntohl(((FPReadRec*)commandRec->cmdBlkAddr)->ReqCount) 
+            > commandRec->replyBufferLen)
+    {
+        ((FPReadRec*)commandRec->cmdBlkAddr)->ReqCount = 
+            htonl(commandRec->replyBufferLen);
+    }
+    
     /* Mask off high byte of addresses because PFI (at least) may
      * put junk in them, and this can cause Marinetti errors. */
     SendDSIMessage(sess, &sess->request,
@@ -187,7 +228,7 @@ void FlagFatalError(Session *sess, Word errorCode) {
     }
 
     if (sess->commandPending) {
-        CompleteCommand(sess, errorCode);
+        CompleteASPCommand(sess, errorCode);
     }
     
     EndSession(sess, TRUE);
@@ -231,11 +272,11 @@ void FinishASPCommand(Session *sess) {
     }
 
 complete:
-    CompleteCommand(sess, 0);
+    CompleteASPCommand(sess, 0);
 }
 
 /* Actions to complete a command, whether successful or not */
-static void CompleteCommand(Session *sess, Word result) {
+void CompleteASPCommand(Session *sess, Word result) {
     SPCommandRec *commandRec;
 
     commandRec = sess->spCommandRec;
diff --git a/aspinterface.h b/aspinterface.h
index e6f1212..ce3cfb1 100644
--- a/aspinterface.h
+++ b/aspinterface.h
@@ -15,6 +15,7 @@
 extern Session sessionTbl[MAX_SESSIONS];
 
 void DispatchASPCommand(SPCommandRec *commandRec);
+void CompleteASPCommand(Session *sess, Word result);
 void FinishASPCommand(Session *sess);
 void FlagFatalError(Session *sess, Word errorCode);
 void PollAllSessions(void);
diff --git a/dsi.c b/dsi.c
index 7531cdc..983a6a7 100644
--- a/dsi.c
+++ b/dsi.c
@@ -142,12 +142,11 @@ top:
                 // Maybe we should do something with them?
                 FinishASPCommand(sess);
             } else {
-                sess->spCommandRec->result = aspSizeErr;
+                CompleteASPCommand(sess, aspBufErr);
             }
+        } else {
+            FinishASPCommand(sess);
         }
-    
-        // TODO correct logic for all cases
-        FinishASPCommand(sess);
         return;
     }
     //Handle a request from the server