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simh-testsetgenerator/sim_tape.h
Mark Pizzolato afb5d6277d TAPE: Extensive cleanup of tape operations (gap, end of medium, format change, etc.) from Dave Bryan 
256. ENHANCEMENT: Add tape runaway support to the simulator tape library.

     OBSERVATION:  The ANSI specifications for NRZI, PE, and GCR tape recording
     mandate a maximum length of 25 feet for erase gaps.  Currently, an erase
     gap of any length is ignored when reading or spacing.  To allow detection
     of non-compliant tape images, the simulator tape library is enhanced to
     halt positioning and return tape runaway status if a gap of 25 feet or more
     is encountered.

     Runaway detection is enabled by calling the tape library to set the tape
     density in bits per inch.  If this call is not made, erase gaps present in
     a tape image are effectively ignored.  Also, with the addition of a
     separate "set density" call, it is no longer necessary to supply the
     density when writing erase gaps.

     RESOLUTION:  Modify "sim_tape_rdlntf" and "sim_tape_rdlntr" (sim_tape.c) to
     detect tape runaway, and add a new MTSE_RUNAWAY status to sim_tape.h.  Add
     new "sim_tape_set_dens" and "sim_tape_show_dens" functions to set and show
     the bits per inch for a unit, respectively, and eliminate the "bpi"
     parameter to "sim_tape_wrgap" in preference to using the density
     established by a previous "sim_tape_set_dens" call.  Add named constants
     to "sim_tape.h" that specify the density.

257. ENHANCEMENT:  Improve performance when reading or spacing over erase gaps.

     OBSERVATION:  Performance when reading or spacing over erase gaps is poor,
     especially in the reverse direction.  Currently, each 4-byte gap marker is
     read individually, and in the reverse direction, each read is preceded by a
     seek to move the file pointer backward.  This combination causes stream
     cache invalidation and a physical disc access for each gap marker.  As a
     single gap consists of over 1000 markers, performance is far worse than if
     a gap was read as a block.

     RESOLUTION:  Modify "sim_tape_rdlntf" and "sim_tape_rdlntr" (sim_tape.c) to
     buffer reads of gap markers.  Using a 128-element buffer, performance
     improves about thirty-fold.

258. PROBLEM:  Writing an end-of-medium positions the tape image after the mark.

     OBSERVATION:  The "sim_tape_wreom" simulator tape library function writes
     an end-of-medium marker on the tape image.  The intent is to erase the
     remainder of the tape.  The "SIMH Magtape Representation and Handling"
     document states that the tape position is not updated by this function.
     However, the function leaves the tape positioned after the marker.

     A subsequent read would stop at the EOM marker.  However, writing a new
     marker over that one would then allow reading of the data following the EOM
     that supposedly had been erased by the original "sim_tape_wreom" call.

     CAUSE:  The tape position is updated by the internal "sim_tape_wrdata" call
     that is used to write the EOM marker, but it is not reset afterward by the
     function.

     RESOLUTION:  Modify "sim_tape_wreom" (sim_tape.c) to reset the tape
     position to point at the EOM marker before returning.  This prevents
     reading past an EOM marker, and a subsequent write will overwrite the
     marker rather than embed it between data records.

259. PROBLEM:  Reading through an erase gap in reverse may return EOM status.

     OBSERVATION:  A reverse read or spacing operation through an erase gap may
     return end-of-medium status.  Reading or spacing forward through the same
     gap works properly.

     CAUSE:  Writing an erase gap over existing records may produce a gap that
     is longer than requested.  This occurs when truncating the last record to
     be overlaid by the gap would leave a record that is shorter than the
     minimum size allowed (eight bytes for the length words plus two bytes for
     the data).  In this case, the gap is lengthened to overlay the entire
     record.  If the new gap size is not evenly divisible by four, a half-gap is
     metadata marker of value 0xFFFF added to the beginning of the gap.

     If a gap that begins with a half-gap marker is written immediately after
     a previous gap, the "seam" between gaps will contain the bytes FE FF FF FF
     ( FF FF ) FE FF FF FF....  Reading forward across this seam will yield a
     metadata value of 0xFFFEFFFF, which is recognized and handled by seeking
     two bytes back to resynchronize reading.  However, reading in reverse will
     yield the value 0xFFFFFFFF, which is interpreted as end-of-medium.

     RESOLUTION:  Modify "sim_tape_rdlntr" (sim_tape.c) to recognize 0xFFFFFFFF
     as a half-gap marker and resynchronize in response.  End of medium cannot
     occur when reading in reverse, as it is impossible to position the tape
     image beyond an EOM marker.  Therefore, any 0xFFFFFFFF value encountered
     must be a half-gap "seam" originating as above.

260. PROBLEM:  sim_tape_wrgap fails when format is changed from SIMH format.

     OBSERVATION:  The HP 2100 magnetic tape simulator supports erase gaps and
     calls sim_tape_wrgap when commanded to write a gap.  However, if a tape
     format other than SIMH format is selected, the call fails with MTSE_FMT.

     CAUSE:  Erase gaps are not supported in formats other than SIMH, but the
     call should not fail.  Instead, the call should be a "no-operation" if the
     underlying format does not support gaps.

     RESOLUTION:  Modify "sim_tape_wrgap" (sim_tape.c) to return MTSE_OK with no
     action performed if a tape format other than SIMH is selected.

261. PROBLEM:  The magnetic tape format of an attached unit may be changed.

     OBSERVATION:  The magnetic tape library supports several tape image
     formats.  The format to use may be specified either by an "ATTACH -F"
     command or by a "SET <unit> FORMAT" command.  The latter calls the
     "sim_tape_set_fmt" function, which allows the format of a file currently
     attached to be changed.  However, the format is an intrinsic property of
     the tape image file, so changing it once the file has been attached makes
     no sense.

     CAUSE:  Oversight.

     RESOLUTION:  Modify "sim_tape_set_fmt" (sim_tape.c) to return an error
     (SCPE_ALATT, "Unit already attached") if the unit is attached.
2014-12-22 05:48:13 -08:00

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/* sim_tape.h: simulator tape support library definitions
Copyright (c) 1993-2008, Robert M Supnik
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
ROBERT M SUPNIK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Except as contained in this notice, the name of Robert M Supnik shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from Robert M Supnik.
23-Jan-12 MP Added support for Logical EOT detection while positioning
05-Feb-11 MP Add Asynch I/O support
30-Aug-06 JDB Added erase gap support
14-Feb-06 RMS Added variable tape capacity
17-Dec-05 RMS Added write support for Paul Pierce 7b format
02-May-05 RMS Added support for Paul Pierce 7b format
*/
#ifndef SIM_TAPE_H_
#define SIM_TAPE_H_ 0
/* SIMH/E11 tape format */
typedef uint32 t_mtrlnt; /* magtape rec lnt */
#define MTR_TMK 0x00000000 /* tape mark */
#define MTR_EOM 0xFFFFFFFF /* end of medium */
#define MTR_GAP 0xFFFFFFFE /* primary gap */
#define MTR_RRGAP 0xFFFFFFFF /* reverse read half gap */
#define MTR_FHGAP 0xFFFEFFFF /* fwd half gap (overwrite) */
#define MTR_RHGAP 0xFFFF0000 /* rev half gap (overwrite) */
#define MTR_M_RHGAP (~0x000080FF) /* range mask for rev gap */
#define MTR_MAXLEN 0x00FFFFFF /* max len is 24b */
#define MTR_ERF 0x80000000 /* error flag */
#define MTR_F(x) ((x) & MTR_ERF) /* record error flg */
#define MTR_L(x) ((x) & ~MTR_ERF) /* record length */
/* TPC tape format */
typedef uint16 t_tpclnt; /* magtape rec lnt */
/* P7B tape format */
#define P7B_SOR 0x80 /* start of record */
#define P7B_PAR 0x40 /* parity */
#define P7B_DATA 0x3F /* data */
#define P7B_DPAR (P7B_PAR|P7B_DATA) /* data and parity */
#define P7B_EOF 0x0F /* eof character */
#define TPC_TMK 0x0000 /* tape mark */
/* Unit flags */
#define MTUF_V_PNU (UNIT_V_UF + 0) /* position not upd */
#define MTUF_V_WLK (UNIT_V_UF + 1) /* write locked */
#define MTUF_V_FMT (UNIT_V_UF + 2) /* tape file format */
#define MTUF_W_FMT 3 /* 3b of formats */
#define MTUF_N_FMT (1u << MTUF_W_FMT) /* number of formats */
#define MTUF_M_FMT ((1u << MTUF_W_FMT) - 1)
#define MTUF_F_STD 0 /* SIMH format */
#define MTUF_F_E11 1 /* E11 format */
#define MTUF_F_TPC 2 /* TPC format */
#define MTUF_F_P7B 3 /* P7B format */
#define MUTF_F_TDF 4 /* TDF format */
#define MTUF_V_UF (MTUF_V_FMT + MTUF_W_FMT)
#define MTUF_PNU (1u << MTUF_V_PNU)
#define MTUF_WLK (1u << MTUF_V_WLK)
#define MTUF_FMT (MTUF_M_FMT << MTUF_V_FMT)
#define MTUF_WRP (MTUF_WLK | UNIT_RO)
#define MT_F_STD (MTUF_F_STD << MTUF_V_FMT)
#define MT_F_E11 (MTUF_F_E11 << MTUF_V_FMT)
#define MT_F_TPC (MTUF_F_TPC << MTUF_V_FMT)
#define MT_F_P7B (MTUF_F_P7B << MTUF_V_FMT)
#define MT_F_TDF (MTUF_F_TDF << MTUF_V_FMT)
#define MT_SET_PNU(u) (u)->flags = (u)->flags | MTUF_PNU
#define MT_CLR_PNU(u) (u)->flags = (u)->flags & ~MTUF_PNU
#define MT_TST_PNU(u) ((u)->flags & MTUF_PNU)
#define MT_GET_FMT(u) (((u)->flags >> MTUF_V_FMT) & MTUF_M_FMT)
/* sim_tape_position Position Flags */
#define MTPOS_V_REW 3
#define MTPOS_M_REW (1u << MTPOS_V_REW) /* Rewind First */
#define MTPOS_V_REV 2
#define MTPOS_M_REV (1u << MTPOS_V_REV) /* Reverse Direction */
#define MTPOS_V_OBJ 1
#define MTPOS_M_OBJ (1u << MTPOS_V_OBJ) /* Objects vs Records/Files */
#define MTPOS_V_DLE 4
#define MTPOS_M_DLE (1u << MTPOS_V_DLE) /* Detect LEOT */
/* Tape density values */
#define MT_DENS_NONE 0 /* density not set */
#define MT_DENS_200 1 /* 200 bpi NRZI */
#define MT_DENS_556 2 /* 556 bpi NRZI */
#define MT_DENS_800 3 /* 800 bpi NRZI */
#define MT_DENS_1600 4 /* 1600 bpi PE */
#define MT_DENS_6250 5 /* 6250 bpi GCR */
#define MTVF_DENS_MASK (((1u << UNIT_S_DF_TAPE) - 1) << UNIT_V_DF_TAPE)
#define MT_DENS(f) (((f) & MTVF_DENS_MASK) >> UNIT_V_DF_TAPE)
#define MT_NONE_VALID (1u << MT_DENS_NONE) /* density not set is valid */
#define MT_200_VALID (1u << MT_DENS_200) /* 200 bpi is valid */
#define MT_556_VALID (1u << MT_DENS_556) /* 556 bpi is valid */
#define MT_800_VALID (1u << MT_DENS_800) /* 800 bpi is valid */
#define MT_1600_VALID (1u << MT_DENS_1600) /* 1600 bpi is valid */
#define MT_6250_VALID (1u << MT_DENS_6250) /* 6250 bpi is valid */
/* Return status codes */
#define MTSE_OK 0 /* no error */
#define MTSE_TMK 1 /* tape mark */
#define MTSE_UNATT 2 /* unattached */
#define MTSE_IOERR 3 /* IO error */
#define MTSE_INVRL 4 /* invalid rec lnt */
#define MTSE_FMT 5 /* invalid format */
#define MTSE_BOT 6 /* beginning of tape */
#define MTSE_EOM 7 /* end of medium */
#define MTSE_RECE 8 /* error in record */
#define MTSE_WRP 9 /* write protected */
#define MTSE_LEOT 10 /* Logical End Of Tape */
#define MTSE_RUNAWAY 11 /* tape runaway */
typedef void (*TAPE_PCALLBACK)(UNIT *unit, t_stat status);
/* Tape Internal Debug flags */
#define MTSE_DBG_DAT 0x0400000 /* Debug Data */
#define MTSE_DBG_POS 0x0800000 /* Debug Positioning activities */
#define MTSE_DBG_STR 0x1000000 /* Debug Tape Structure */
/* Prototypes */
t_stat sim_tape_attach_ex (UNIT *uptr, char *cptr, uint32 dbit, int completion_delay);
t_stat sim_tape_attach (UNIT *uptr, char *cptr);
t_stat sim_tape_detach (UNIT *uptr);
t_stat sim_tape_attach_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, char *cptr);
t_stat sim_tape_rdrecf (UNIT *uptr, uint8 *buf, t_mtrlnt *bc, t_mtrlnt max);
t_stat sim_tape_rdrecf_a (UNIT *uptr, uint8 *buf, t_mtrlnt *bc, t_mtrlnt max, TAPE_PCALLBACK callback);
t_stat sim_tape_rdrecr (UNIT *uptr, uint8 *buf, t_mtrlnt *bc, t_mtrlnt max);
t_stat sim_tape_rdrecr_a (UNIT *uptr, uint8 *buf, t_mtrlnt *bc, t_mtrlnt max, TAPE_PCALLBACK callback);
t_stat sim_tape_wrrecf (UNIT *uptr, uint8 *buf, t_mtrlnt bc);
t_stat sim_tape_wrrecf_a (UNIT *uptr, uint8 *buf, t_mtrlnt bc, TAPE_PCALLBACK callback);
t_stat sim_tape_wrtmk (UNIT *uptr);
t_stat sim_tape_wrtmk_a (UNIT *uptr, TAPE_PCALLBACK callback);
t_stat sim_tape_wreom (UNIT *uptr);
t_stat sim_tape_wreom_a (UNIT *uptr, TAPE_PCALLBACK callback);
t_stat sim_tape_wreomrw (UNIT *uptr);
t_stat sim_tape_wreomrw_a (UNIT *uptr, TAPE_PCALLBACK callback);
t_stat sim_tape_wrgap (UNIT *uptr, uint32 gaplen);
t_stat sim_tape_wrgap_a (UNIT *uptr, uint32 gaplen, TAPE_PCALLBACK callback);
t_stat sim_tape_sprecf (UNIT *uptr, t_mtrlnt *bc);
t_stat sim_tape_sprecf_a (UNIT *uptr, t_mtrlnt *bc, TAPE_PCALLBACK callback);
t_stat sim_tape_sprecsf (UNIT *uptr, uint32 count, uint32 *skipped);
t_stat sim_tape_sprecsf_a (UNIT *uptr, uint32 count, uint32 *skipped, TAPE_PCALLBACK callback);
t_stat sim_tape_spfilef (UNIT *uptr, uint32 count, uint32 *skipped);
t_stat sim_tape_spfilef_a (UNIT *uptr, uint32 count, uint32 *skipped, TAPE_PCALLBACK callback);
t_stat sim_tape_spfilebyrecf (UNIT *uptr, uint32 count, uint32 *skipped, uint32 *recsskipped, t_bool check_leot);
t_stat sim_tape_spfilebyrecf_a (UNIT *uptr, uint32 count, uint32 *skipped, uint32 *recsskipped, t_bool check_leot, TAPE_PCALLBACK callback);
t_stat sim_tape_sprecr (UNIT *uptr, t_mtrlnt *bc);
t_stat sim_tape_sprecr_a (UNIT *uptr, t_mtrlnt *bc, TAPE_PCALLBACK callback);
t_stat sim_tape_sprecsr (UNIT *uptr, uint32 count, uint32 *skipped);
t_stat sim_tape_sprecsr_a (UNIT *uptr, uint32 count, uint32 *skipped, TAPE_PCALLBACK callback);
t_stat sim_tape_spfiler (UNIT *uptr, uint32 count, uint32 *skipped);
t_stat sim_tape_spfiler_a (UNIT *uptr, uint32 count, uint32 *skipped, TAPE_PCALLBACK callback);
t_stat sim_tape_spfilebyrecr (UNIT *uptr, uint32 count, uint32 *skipped, uint32 *recsskipped);
t_stat sim_tape_spfilebyrecr_a (UNIT *uptr, uint32 count, uint32 *skipped, uint32 *recsskipped, TAPE_PCALLBACK callback);
t_stat sim_tape_rewind (UNIT *uptr);
t_stat sim_tape_rewind_a (UNIT *uptr, TAPE_PCALLBACK callback);
t_stat sim_tape_position (UNIT *uptr, uint32 flags, uint32 recs, uint32 *recskipped, uint32 files, uint32 *fileskipped, uint32 *objectsskipped);
t_stat sim_tape_position_a (UNIT *uptr, uint32 flags, uint32 recs, uint32 *recsskipped, uint32 files, uint32 *filesskipped, uint32 *objectsskipped, TAPE_PCALLBACK callback);
t_stat sim_tape_reset (UNIT *uptr);
t_bool sim_tape_bot (UNIT *uptr);
t_bool sim_tape_wrp (UNIT *uptr);
t_bool sim_tape_eot (UNIT *uptr);
t_stat sim_tape_set_fmt (UNIT *uptr, int32 val, char *cptr, void *desc);
t_stat sim_tape_show_fmt (FILE *st, UNIT *uptr, int32 val, void *desc);
t_stat sim_tape_set_capac (UNIT *uptr, int32 val, char *cptr, void *desc);
t_stat sim_tape_show_capac (FILE *st, UNIT *uptr, int32 val, void *desc);
t_stat sim_tape_set_dens (UNIT *uptr, int32 val, char *cptr, void *desc);
t_stat sim_tape_show_dens (FILE *st, UNIT *uptr, int32 val, void *desc);
t_stat sim_tape_set_asynch (UNIT *uptr, int latency);
t_stat sim_tape_clr_asynch (UNIT *uptr);
void sim_tape_data_trace (UNIT *uptr, const uint8 *data, size_t len, const char* txt, int detail, uint32 reason);
#endif
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