--- /sys/src/9k/386/sdata.c
+++ /sys/src/9k/386/sdata.c
@@ -1487,17 +1487,17 @@ atagenio(Drive* drive, uchar* cmd, int clen)
 	 * Fail any command with a LUN except INQUIRY which
 	 * will return 'logical unit not supported'.
 	 */
-	if((cmd[1]>>5) && cmd[0] != 0x12)
+	if((cmd[1]>>5) && cmd[0] != ScmdInq)
 		return atasetsense(drive, SDcheck, 0x05, 0x25, 0);
 
 	switch(cmd[0]){
 	default:
 		return atasetsense(drive, SDcheck, 0x05, 0x20, 0);
 
-	case 0x00:			/* test unit ready */
+	case ScmdTur:			/* test unit ready */
 		return SDok;
 
-	case 0x03:			/* request sense */
+	case ScmdRsense:		/* request sense */
 		if(cmd[4] < sizeof(drive->sense))
 			len = cmd[4];
 		else
@@ -1508,7 +1508,7 @@ atagenio(Drive* drive, uchar* cmd, int clen)
 		}
 		return SDok;
 
-	case 0x12:			/* inquiry */
+	case ScmdInq:			/* inquiry */
 		if(cmd[4] < sizeof(drive->inquiry))
 			len = cmd[4];
 		else
@@ -1519,14 +1519,14 @@ atagenio(Drive* drive, uchar* cmd, int clen)
 		}
 		return SDok;
 
-	case 0x1B:			/* start/stop unit */
+	case ScmdStart:			/* start/stop unit */
 		/*
 		 * NOP for now, can use the power management feature
 		 * set later.
 		 */
 		return SDok;
 
-	case 0x25:			/* read capacity */
+	case ScmdRcapacity:			/* read capacity */
 		if((cmd[1] & 0x01) || cmd[2] || cmd[3])
 			return atasetsense(drive, SDcheck, 0x05, 0x24, 0);
 		if(drive->data == nil || drive->dlen < 8)
@@ -1548,7 +1548,7 @@ atagenio(Drive* drive, uchar* cmd, int clen)
 		drive->data += 8;
 		return SDok;
 
-	case 0x9E:			/* long read capacity */
+	case ScmdRcapacity16:
 		if((cmd[1] & 0x01) || cmd[2] || cmd[3])
 			return atasetsense(drive, SDcheck, 0x05, 0x24, 0);
 		if(drive->data == nil || drive->dlen < 8)
@@ -1574,14 +1574,14 @@ atagenio(Drive* drive, uchar* cmd, int clen)
 		drive->data += 12;
 		return SDok;
 
-	case 0x28:			/* read (10) */
-	case 0x88:			/* long read (16) */
-	case 0x2a:			/* write (10) */
-	case 0x8a:			/* long write (16) */
-	case 0x2e:			/* write and verify (10) */
+	case ScmdExtread:
+	case ScmdExtwrite:
+	case ScmdExtwritever:
+	case ScmdRead16:
+	case ScmdWrite16:
 		break;
 
-	case 0x5A:
+	case ScmdMsense10:
 		return atamodesense(drive, cmd);
 	}
 
@@ -1674,8 +1674,8 @@ atario(SDreq* r)
 	 * effort. Read/write(6) are easy.
 	 */
 	switch(r->cmd[0]){
-	case 0x08:			/* read */
-	case 0x0A:			/* write */
+	case ScmdRead:
+	case ScmdWrite:
 		cmdp = cmd10;
 		memset(cmdp, 0, sizeof(cmd10));
 		cmdp[0] = r->cmd[0]|0x20;
--- /sys/src/9k/386/sdiahci.c
+++ /sys/src/9k/386/sdiahci.c
@@ -1523,7 +1523,7 @@ ahcibuild(Drive *d, uchar *cmd, void *data, int n, vlong lba)
 	static uchar tab[2][2] = { 0xc8, 0x25, 0xca, 0x35, };
 
 	pm = &d->portm;
-	dir = *cmd != 0x28;
+	dir = *cmd != ScmdExtread;
 	llba = pm->feat&Dllba? 1: 0;
 	acmd = tab[dir][llba];
 	qlock(pm);
@@ -1769,10 +1769,10 @@ retry:
 		case SDperworm:
 		case SDpercd:
 			switch(cmd[0]){
-			case 0x0a:		/* write (6?) */
-			case 0x2a:		/* write (10) */
-			case 0x8a:		/* long write (16) */
-			case 0x2e:		/* write and verify (10) */
+			case ScmdWrite:
+			case ScmdExtwrite:
+			case ScmdExtwritever:
+			case ScmdWrite16:
 				wormwrite = 1;
 				break;
 			}
@@ -1819,7 +1819,7 @@ iario(SDreq *r)
 	name = d->unit->name;
 	p = d->port;
 
-	if(r->cmd[0] == 0x35 || r->cmd[0] == 0x91){
+	if(*cmd == ScmdSynccache || *cmd == ScmdSynccache16){
 		if(flushcache(d) == 0)
 			return sdsetsense(r, SDok, 0, 0, 0);
 		return sdsetsense(r, SDcheck, 3, 0xc, 2);
@@ -1830,7 +1830,7 @@ iario(SDreq *r)
 		return i;
 	}
 
-	if(*cmd != 0x28 && *cmd != 0x2a){
+	if(*cmd != ScmdExtread && *cmd != ScmdExtwrite){
 		print("%s: bad cmd %.2#ux\n", name, cmd[0]);
 		r->status = SDcheck;
 		return SDcheck;
--- /sys/src/9k/port/devsd.c
+++ /sys/src/9k/port/devsd.c
@@ -963,8 +963,8 @@ sdfakescsi(SDreq *r, void *info, int ilen)
 	 * Rewrite read(6)/write(6) into read(10)/write(10).
 	 */
 	switch(cmd[0]){
-	case 0x08:	/* read */
-	case 0x0A:	/* write */
+	case ScmdRead:
+	case ScmdWrite:
 		cmd[9] = 0;
 		cmd[8] = cmd[4];
 		cmd[7] = 0;
@@ -983,17 +983,17 @@ sdfakescsi(SDreq *r, void *info, int ilen)
 	 * Fail any command with a LUN except INQUIRY which
 	 * will return 'logical unit not supported'.
 	 */
-	if((cmd[1]>>5) && cmd[0] != 0x12)
+	if((cmd[1]>>5) && cmd[0] != ScmdInq)
 		return sdsetsense(r, SDcheck, 0x05, 0x25, 0);
 
 	switch(cmd[0]){
 	default:
 		return sdsetsense(r, SDcheck, 0x05, 0x20, 0);
 
-	case 0x00:	/* test unit ready */
+	case ScmdTur:		/* test unit ready */
 		return sdsetsense(r, SDok, 0, 0, 0);
 
-	case 0x03:	/* request sense */
+	case ScmdRsense:	/* request sense */
 		if(cmd[4] < sizeof unit->sense)
 			len = cmd[4];
 		else
@@ -1004,7 +1004,7 @@ sdfakescsi(SDreq *r, void *info, int ilen)
 		}
 		return sdsetsense(r, SDok, 0, 0, 0);
 
-	case 0x12:	/* inquiry */
+	case ScmdInq:		/* inquiry */
 		if(cmd[4] < sizeof unit->inquiry)
 			len = cmd[4];
 		else
@@ -1015,13 +1015,13 @@ sdfakescsi(SDreq *r, void *info, int ilen)
 		}
 		return sdsetsense(r, SDok, 0, 0, 0);
 
-	case 0x1B:	/* start/stop unit */
+	case ScmdStart:		/* start/stop unit */
 		/*
 		 * nop for now, can use power management later.
 		 */
 		return sdsetsense(r, SDok, 0, 0, 0);
 
-	case 0x25:	/* read capacity */
+	case ScmdRcapacity:	/* read capacity */
 		if((cmd[1] & 0x01) || cmd[2] || cmd[3])
 			return sdsetsense(r, SDcheck, 0x05, 0x24, 0);
 		if(r->data == nil || r->dlen < 8)
@@ -1044,7 +1044,7 @@ sdfakescsi(SDreq *r, void *info, int ilen)
 		r->rlen = p - (uchar*)r->data;
 		return sdsetsense(r, SDok, 0, 0, 0);
 
-	case 0x9E:	/* long read capacity */
+	case ScmdRcapacity16:	/* long read capacity */
 		if((cmd[1] & 0x01) || cmd[2] || cmd[3])
 			return sdsetsense(r, SDcheck, 0x05, 0x24, 0);
 		if(r->data == nil || r->dlen < 8)
@@ -1070,13 +1070,13 @@ sdfakescsi(SDreq *r, void *info, int ilen)
 		r->rlen = p - (uchar*)r->data;
 		return sdsetsense(r, SDok, 0, 0, 0);
 
-	case 0x5A:	/* mode sense */
+	case ScmdMsense10:	/* mode sense */
 		return sdmodesense(r, cmd, info, ilen);
 
-	case 0x28:	/* read */
-	case 0x2A:	/* write */
-	case 0x88:	/* read16 */
-	case 0x8a:	/* write16 */
+	case ScmdExtread:
+	case ScmdExtwrite:
+	case ScmdRead16:
+	case ScmdWrite16:
 		return SDnostatus;
 	}
 }
--- /sys/src/9k/port/sd.h
+++ /sys/src/9k/port/sd.h
@@ -1,6 +1,8 @@
 /*
  * Storage Device.
  */
+#include <diskcmd.h>
+
 typedef struct SDev SDev;
 typedef struct SDifc SDifc;
 typedef struct SDio SDio;
old mode 100644
--- /sys/src/9k/port/sdaoe.c
+++ /sys/src/9k/port/sdaoe.c
@@ -449,14 +449,13 @@ aoerio(SDreq *r)
 	cmd = r->cmd;
 	name = unit->name;
 
-	if(r->cmd[0] == 0x35 || r->cmd[0] == 0x91){
+	if(*cmd == ScmdSynccache || *cmd == ScmdSynccache16)
 //		qlock(c);
 //		i = flushcache();
 //		qunlock(c);
 //		if(i == 0)
 //			return sdsetsense(r, SDok, 0, 0, 0);
 		return sdsetsense(r, SDcheck, 3, 0xc, 2);
-	}
 
 	if((i = sdfakescsi(r, c->ident, sizeof c->ident)) != SDnostatus){
 		r->status = i;
@@ -464,12 +463,12 @@ aoerio(SDreq *r)
 	}
 
 	switch(*cmd){
-	case 0x88:
-	case 0x28:
+	case ScmdRead16:
+	case ScmdExtread:
 		rio = c->c->dev->read;
 		break;
-	case 0x8a:
-	case 0x2a:
+	case ScmdWrite16:
+	case ScmdExtwrite:
 		rio = c->c->dev->write;
 		break;
 	default:
--- /sys/src/9k/port/sdscsi.c
+++ /sys/src/9k/port/sdscsi.c
@@ -203,7 +203,7 @@ scsionline(SDunit* unit)
 		 */
 		r->write = 0;
 		memset(r->cmd, 0, sizeof(r->cmd));
-		r->cmd[0] = 0x25;
+		r->cmd[0] = ScmdRcapacity;
 		r->cmd[1] = r->lun<<5;
 		r->clen = 10;
 		r->data = p;
@@ -311,9 +311,9 @@ scsifmt10(SDreq *r, int write, int lun, ulong nb, uvlong bno)
 
 	c = r->cmd;
 	if(write == 0)
-		c[0] = 0x28;
+		c[0] = ScmdExtread;
 	else
-		c[0] = 0x2A;
+		c[0] = ScmdExtwrite;
 	c[1] = lun<<5;
 	c[2] = bno>>24;
 	c[3] = bno>>16;
@@ -334,9 +334,9 @@ scsifmt16(SDreq *r, int write, int lun, ulong nb, uvlong bno)
 
 	c = r->cmd;
 	if(write == 0)
-		c[0] = 0x88;
+		c[0] = ScmdRead16;
 	else
-		c[0] = 0x8A;
+		c[0] = ScmdWrite16;
 	c[1] = lun<<5;		/* so wrong */
 	c[2] = bno>>56;
 	c[3] = bno>>48;