From 5437b534a847768d6910f2e9dacfe2e1e1b8d9d9 Mon Sep 17 00:00:00 2001
From: Richard Cornwell <rcornwell@github.com>
Date: Tue, 22 Dec 2020 20:39:08 -0500
Subject: [PATCH] IBM360: Added command that VM/370 used to detect new disk.

---
 IBM360/ibm360_dasd.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/IBM360/ibm360_dasd.c b/IBM360/ibm360_dasd.c
index e953f0e..67fb896 100644
--- a/IBM360/ibm360_dasd.c
+++ b/IBM360/ibm360_dasd.c
@@ -99,6 +99,7 @@
 #define DK_ERASE           0x11       /* Erase to end of track */
 #define DK_RD_SECT         0x22       /* Read sector counter */
 #define DK_SETSECT         0x23       /* Set sector */
+#define DK_RD_BUFF         0xA4       /* Read and reset record log */
 #define DK_MT              0x80       /* Multi track flag */
 
 /* u3 */
@@ -1812,6 +1813,20 @@ wrckd:
          chan_end(addr, SNS_CHNEND|SNS_DEVEND);
          break;
 
+    case DK_RD_BUFF & 0x7f:
+         if (disk_type[type].sen_cnt > 6 && (cmd = uptr->CMD & 0xff) == DK_RD_BUFF) {
+             ch = 0;
+             for (i = 0; i < 32; i++) {
+                 if (chan_write_byte(addr, &ch))
+                     break;
+             }
+             uptr->LCMD = 0;
+             uptr->CMD &= ~(0xff);
+             chan_end(addr, SNS_CHNEND|SNS_DEVEND);
+             break;
+         }
+         /* Fall through */
+
     case DK_SPACE:           /* Space record */
          /* Not implemented yet */
     default: