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pkimpel.retro-b5500/webUI/B5500DiskUnit.js
paul.kimpel@digm.com 72fca54c23 1. Release emulator version 0.14.
2. Fix normalization and rounding problems in Processor.
3. Fix Card-Load-Select -- emulator now boots from cards.
4. Commit LDCNTRL label and end cards to source CONTROL.DECK.job
5. Delete unused activeIOUnit property in all I/O drivers.
6. Change CardReader to reset file selector control when hopper becomes empty, instead of when START button is clicked.
7. Minor adjustments to CentralControl annunciator layout and behavior on Console.
8. Increase SPO paper scroll-back to 1500 lines (was 500).
9. Correct Card-Load-Select behavior in SyllableDebugger.
10. Implement setCallback() to replace setImmediate() in SyllableDebugger.
2013-10-06 18:26:47 +00:00

482 lines
23 KiB
JavaScript

/***********************************************************************
* retro-b5500/emulator B5500DiskUnit.js
************************************************************************
* Copyright (c) 2013, Nigel Williams and Paul Kimpel.
* Licensed under the MIT License, see
* http://www.opensource.org/licenses/mit-license.php
************************************************************************
* B5500 Disk File Control Unit module.
*
* Defines a peripheral unit type for the Disk File Control Unit used with
* Burroughs Model I and Model IB Head-per-Track disk units. The DFCU is the
* addressable unit to the B5500. This module manages the Electronic Units (EU)
* and Storage Units (SU) that make up the physical disk storage facility.
*
* Physical storage in this implementation is provided by a W3C IndexedDB
* database local to the browser in which the emulator is running. This database
* must have been previously initialized; see tools/B5500ColdLoader.html.
*
* The database consists of a CONFIG object store and some number of EUn object
* stores, where n is in 0..9. The CONFIG store contains an "eus" member that
* specifies the total number of EU objects, plus an "EUn" member that specifies
* the size of that EU in 240-character segments. There may be gaps in the EU
* numbering, but the EU sizes should be specified in increments of 40,000 up to
* a maximum of 200,000 (for Model I) or 400,000 (for Model IB "slow" disks).
*
* Within an EU, segments are represented in the database as 240-byte Uint8Array
* objects, each with a database key corresponding to its numeric segment address.
* The segments in an EU are not pre-allocated, but are created as they are
* written to by IDB put() methods. When reading, any unallocated segments are
* returned with their bytes set to 0x23 (#), which will be translated by the
* IOU to BIC "0" for alpha mode and BIC "#" for binary mode.
*
* At present, disk write lockout is not supported. When there are two DFCUs in
* the system, the presence of a Disk File Exchange is assumed, allowing either
* DFCU to access any EU. Thus this implementation is currently limited to a
* maximum of 10 EUs (480 million characters).
*
* Note that all disk I/O is done in units of 240-character segments. The
* interface with the I/O Unit uses lengths in terms of characters, however.
* All lengths SHOULD be multiples of 240 characters; any other values will be
* rounded up to the next multiple of 240. The I/O Unit is responsible for any
* padding or truncation to account for differences between the segment count
* and word count in the IOD. This implementation ignores binary vs. alpha mode
* and assumes the IOU does any necessary translation.
*
* The starting disk segment address for an I/O is passed in the "control"
* parameter to each of the I/O methods. This is an an alphanumeric value in
* the B5500 memory and I/O Unit. The I/O unit translates this value to binary
* for the "control" parameter. The low-order six decimal digits of the value
* comprise the segment address within the EU. The seventh decimal digit is the
* EU number. Any other portion of the value is ignored.
*
* The DFCU's "read check" operation is asynchronous with respect to the IOU, and
* the I/O operation itself completes almost immediately. Because of this, any
* error reporting for the read check is deferred until the next I/O operation
* (typically an interrogate) against the unit. Therefore, the error mask is
* cleared at the end of each disk I/O operation (except for read check) instead
* of at the beginning, and new errors are OR-ed with any errors persisting from
* the prior operation.
*
* This module attempts to simulate actual disk activity times by delaying the
* finish() call by an amount of time computed from the numbers of sectors
* requested and the Model I SU's average 96KC transfer rate, plus a random
* distribution across its 40ms max rotational latency time.
************************************************************************
* 2013-01-19 P.Kimpel
* Original version, cloned from B5500DummyUnit.js.
***********************************************************************/
"use strict";
/**************************************/
function B5500DiskUnit(mnemonic, index, designate, statusChange, signal) {
/* Constructor for the DiskUnit object */
this.mnemonic = mnemonic; // Unit mnemonic
this.index = index; // Ready-mask bit number
this.designate = designate; // IOD unit designate number
this.statusChange = statusChange; // external function to call for ready-status change
this.signal = signal; // external function to call for special signals (e.g,. SPO input request)
this.timer = null; // setTimeout() token
this.initiateStamp = 0; // timestamp of last initiation (set by IOUnit)
this.clear();
}
B5500DiskUnit.prototype.dbName = "B5500DiskUnit"; // IndexedDB database name
B5500DiskUnit.prototype.dbVersion = 1; // current IDB database version
B5500DiskUnit.prototype.configName = "CONFIG"; // database configuration store name
B5500DiskUnit.prototype.euPrefix = "EU"; // prefix for EU object store names
B5500DiskUnit.prototype.charXferRate = 96000; // avg. transfer rate, characters/sec (Model I SU)
B5500DiskUnit.prototype.maxLatency = 0.040; // max rotational latency, sec (Model I SU)
/**************************************/
B5500DiskUnit.prototype.clear = function clear() {
/* Initializes (and if necessary, creates) the processor state */
this.ready = false; // ready status
this.busy = false; // busy status
this.errorMask = 0; // error mask for finish()
this.finish = null; // external function to call for I/O completion
this.startStamp = null; // I/O starting timestamp
this.config = null; // copy of CONFIG store contents
this.disk = null; // the IDB database object
this.openDatabase(); // attempt to open the IDB database
};
/**************************************/
B5500DiskUnit.genericDBError = function genericDBError(ev) {
/* Formats a generic alert when otherwise-unhandled database errors occur */
var disk = ev.currentTarget.result;
this.errorMask |= 0x20; // set a generic disk-parity error
alert("Database for \"" + this.mnemonic + "\" error: " + ev.target.result.error);
this.finish(this.errorMask, 0);
this.errorMask = 0;
};
/**************************************/
B5500DiskUnit.prototype.copySegment = function copySegment(seg, buffer, offset) {
/* Copies the bytes from a single segment Uint8Array object to "buffer" starting
at "offset" for 240 bytes. If "seg" is undefined, copies zero bytes instead */
var x;
if (seg) {
for (x=0; x<240; x++) {
buffer[offset+x] = seg[x];
}
} else {
for (x=offset+239; x>=offset; x--) {
buffer[x] = 0x23; // ASCII "#", translates as alpha to BIC "0" = @00
}
}
};
/**************************************/
B5500DiskUnit.prototype.openDatabase = function openDataBase() {
/* Attempts to open the disk subsystem database specified by this.dbName and
this.dbVersion. If successful, sets this.disk to the IDB object and sets the
DFCU to ready status */
var req;
var db = null;
var that = this;
that.statusChange(0); // initially force DFCU status to not ready
req = indexedDB.open(that.dbName, that.dbVersion);
req.onerror = function idbOpenOnerror(ev) {
alert("Cannot open " + that.mnemonic + " database: " + ev.target.error);
};
req.onblocked = function idbOpenOnblocked(ev) {
alert("Database.open is blocked -- cannot continue");
};
req.onupgradeneeded = function idbOpenOnupgradeneeded(ev) {
alert("Database requires version upgrade -- cannot continue");
};
req.onsuccess = function idbOpenOnsuccess(ev) {
that.disk = ev.target.result; // save the object reference globally for later use
that.disk.onerror = function idbCONFIGGetOnerror(ev) {
alert("Database for \"" + that.mnemonic + "\" CONFIG get error: " + ev.target.result.error);
};
that.disk.transaction("CONFIG").objectStore("CONFIG").get(0).onsuccess = function idbCONFIGGetOnsuccess(ev) {
that.config = ev.target.result;
that.statusChange(1); // report the DFCU as ready to Central Control
// Set up the generic error handler
that.disk.onerror = function idbGenericOnError(ev) {
that.genericIDBError(ev);
};
};
};
};
/**************************************/
B5500DiskUnit.prototype.read = function read(finish, buffer, length, mode, control) {
/* Initiates a read operation on the unit. "length" is in characters; segment address
is in "control". "mode" is ignored (any translation would have been done by IOU) */
var bx = 0; // current buffer offset
var euSize; // max seg size for EU
var finishTime; // predicted time of I/O completion, ms
var range; // key range for multi-segment read
var req; // IDB request object
var that = this; // local object context
var txn; // IDB transaction object
this.finish = finish; // for global error handler
var segs = Math.floor((length+239)/240);
var segAddr = control % 1000000; // starting seg address
var euNumber = (control % 10000000 - segAddr)/1000000;
var euName = this.euPrefix + euNumber;
var endAddr = segAddr+segs-1; // ending seg address
euSize = this.config[euName];
if (!euSize) { // EU does not exist
finish(this.errorMask | 0x20, 0); // set D27F for EU not ready/not present
this.errorMask = 0;
} else if (segAddr < 0) {
finish(this.errorMask | 0x20, 0); // set D27F for invalid starting seg address
this.errorMask = 0;
} else {
if (endAddr >= euSize) { // if read is past end of disk
this.errorMask |= 0x20; // set D27F for invalid seg address
segs = euSize-segAddr; // compute number of segs possible to read
length = segs*240; // recompute length and ending seg address
endAddr = euSize-1;
}
finishTime = this.initiateStamp +
(Math.random()*this.maxLatency + segs*240/this.charXferRate)*1000;
if (segs < 1) { // No length specified, so just finish the I/O
finish(this.errorMask, 0);
this.errorMask = 0;
} else if (segs < 2) { // A single-segment read
req = this.disk.transaction(euName).objectStore(euName).get(segAddr);
req.onsuccess = function singleReadOnsuccess(ev) {
that.copySegment(ev.target.result, buffer, 0);
this.timer = setTimeout(function singleReadTimeout() {
finish(that.errorMask, length);
that.errorMask = 0;
}, finishTime - new Date().getTime());
}
} else { // A multi-segment read
range = IDBKeyRange.bound(segAddr, endAddr);
txn = this.disk.transaction(euName);
req = txn.objectStore(euName).openCursor(range);
req.onsuccess = function rangeReadOnsuccess(ev) {
var cursor = ev.target.result;
if (cursor) { // found a segment at some address in range
// fill buffer with zeroes for any unallocated segments
while (cursor.key > segAddr) {
that.copySegment(null, buffer, bx);
bx += 240;
segAddr++;
}
// copy the segment data to the buffer and request next seg
that.copySegment(cursor.value, buffer, bx);
bx += 240;
segAddr++;
cursor.continue();
} else { // at end of range
// fill buffer with zeroes for any remaining segments in range
while (endAddr > segAddr) {
that.copySegment(null, buffer, bx);
bx += 240;
segAddr++;
}
this.timer = setTimeout(function rangeReadTimeout() {
finish(that.errorMask, length);
that.errorMask = 0;
}, finishTime - new Date().getTime());
}
};
}
}
};
/**************************************/
B5500DiskUnit.prototype.space = function space(finish, length, control) {
/* Initiates a space operation on the unit */
finish(0x04, 0); // report unit not ready
};
/**************************************/
B5500DiskUnit.prototype.write = function write(finish, buffer, length, mode, control) {
/* Initiates a write operation on the unit. "length" is in characters; segment address
is in "control". "mode" is ignored (any translation will done by the IOU) */
var bx = 0; // current buffer offset
var eu; // IDB object store for EU
var euSize; // max seg size for EU
var finishTime; // predicted time of I/O completion, ms
var req; // IDB request object
var that = this; // local object context
var txn; // IDB transaction object
this.finish = finish; // for global error handler
var segs = Math.floor((length+239)/240);
var segAddr = control % 1000000; // starting seg address
var euNumber = (control % 10000000 - segAddr)/1000000;
var euName = this.euPrefix + euNumber;
var endAddr = segAddr+segs-1; // ending seg address
euSize = this.config[euName];
if (!euSize) { // EU does not exist
finish(this.errorMask | 0x20, 0); // set D27F for EU not ready
this.errorMask = 0;
} else if (segAddr < 0) {
finish(this.errorMask | 0x20, 0); // set D27F for invalid starting seg address
this.errorMask = 0;
} else {
if (endAddr >= euSize) { // if read is past end of disk
this.errorMask |= 0x20; // set D27F for invalid seg address
segs = euSize-segAddr; // compute number of segs possible to read
length = segs*240; // recompute length and ending seg address
endAddr = euSize-1;
}
finishTime = this.initiateStamp +
(Math.random()*this.maxLatency + segs*240/this.charXferRate)*1000;
// No length specified, so just finish the I/O
if (segs < 1) {
finish(this.errorMask, 0);
this.errorMask = 0;
// Do the write
} else {
txn = this.disk.transaction(euName, "readwrite")
txn.oncomplete = function writeComplete(ev) {
this.timer = setTimeout(function writeTimeout() {
finish(that.errorMask, length);
that.errorMask = 0;
}, finishTime - new Date().getTime());
};
eu = txn.objectStore(euName);
for (; segAddr<=endAddr; segAddr++) {
eu.put(buffer.subarray(bx, bx+240), segAddr);
bx += 240;
}
}
}
};
/**************************************/
B5500DiskUnit.prototype.erase = function erase(finish, length) {
/* Initiates an erase operation on the unit */
finish(0x04, 0); // report unit not ready
};
/**************************************/
B5500DiskUnit.prototype.rewind = function rewind(finish) {
/* Initiates a rewind operation on the unit */
finish(0x04, 0); // report unit not ready
};
/**************************************/
B5500DiskUnit.prototype.readCheck = function readCheck(finish, length, control) {
/* Initiates a read check operation on the unit. "length" is in characters;
segment address is in "control". "mode" is ignored. This is essentially a
read without any data transfer to memory. Note that the errorMask is NOT
zeroed at the end of the I/O -- it will be reported with the next I/O */
var euSize; // max seg size for EU
var finishTime; // predicted time of I/O completion, ms
var range; // key range for multi-segment read
var req; // IDB request object
var that = this; // local object context
var txn; // IDB transaction object
this.finish = finish; // for global error handler
var segs = Math.floor((length+239)/240);
var segAddr = control % 1000000; // starting seg address
var euNumber = (control % 10000000 - segAddr)/1000000;
var euName = this.euPrefix + euNumber;
var endAddr = segAddr+segs-1; // ending seg address
this.errorMask = 0; // clear any prior error mask
euSize = this.config[euName];
if (!euSize) { // EU does not exist
finish(this.errorMask | 0x20, 0); // set D27F for EU not ready
this.signal();
// DO NOT clear the error mask
} else if (segAddr < 0) {
finish(this.errorMask | 0x20, 0); // set D27F for invalid starting seg address
this.signal();
// DO NOT clear the error mask
} else {
if (endAddr >= euSize) { // if read is past end of disk
this.errorMask |= 0x20; // set D27F for invalid seg address
segs = euSize-segAddr; // compute number of segs possible to read
length = segs*240; // recompute length and ending seg address
endAddr = euSize-1;
}
finishTime = this.initiateStamp +
(Math.random()*this.maxLatency + segs*240/this.charXferRate)*1000;
if (segs < 1) { // No length specified, so just finish the I/O
finish(this.errorMask, 0);
this.signal();
// DO NOT clear the error mask -- will return it on the next interrogate
} else { // A multi-segment read
range = IDBKeyRange.bound(segAddr, endAddr);
txn = this.disk.transaction(euName);
finish(that.errorMask, length); // post I/O complete now -- DFCU will signal when check finished
req = txn.objectStore(euName).openCursor(range);
req.onsuccess = function readCheckOnsuccess(ev) {
var cursor = ev.target.result;
if (cursor) { // found a segment at some address in range
cursor.continue();
} else { // at end of range
this.timer = setTimeout(function readCheckTimeout() {
that.signal();
// DO NOT clear the error mask
}, finishTime - new Date().getTime());
}
};
}
}
};
/**************************************/
B5500DiskUnit.prototype.readInterrogate = function readInterrogate(finish, control) {
/* Initiates a read interrogate operation on the unit. This serves only to
check the addresss for validity and to return any errorMask from a prior
read check operation. This implementation assumes completion will be delayed
by a random amount of time based on rotational latency for the EU to search for
the address */
var euSize; // max seg size for EU
var segAddr = control % 1000000; // starting seg address
var euNumber = (control % 10000000 - segAddr)/1000000;
var euName = this.euPrefix + euNumber;
var that = this;
this.finish = finish; // for global error handler
euSize = this.config[euName];
if (!euSize) { // EU does not exist
finish(this.errorMask | 0x20, 0); // set D27F for EU not ready
this.errorMask = 0;
} else {
if (segAddr < 0 || segAddr >= euSize) { // if read is past end of disk
this.errorMask |= 0x20; // set D27F for invalid seg address
}
this.timer = setTimeout(function readInterrogateTimeout() {
finish(that.errorMask, length);
that.errorMask = 0;
}, Math.random()*this.maxLatency*1000 + this.initiateStamp - new Date().getTime());
}
};
/**************************************/
B5500DiskUnit.prototype.writeInterrogate = function writeInterrogate(finish, control) {
/* Initiates a write interrogate operation on the unit. This serves only to
check the addresss for validity and to return any errorMask from a prior
read check operation. This implementation assumes completion will be delayed
by a random amount of time based on rotational latency for the EU to search for
the address */
/* Note: until disk write lockout is implemented, this operation is identical
to readInterrogate() */
var euSize; // max seg size for EU
var segAddr = control % 1000000; // starting seg address
var euNumber = (control % 10000000 - segAddr)/1000000;
var euName = this.euPrefix + euNumber;
var that = this;
this.finish = finish; // for global error handler
euSize = this.config[euName];
if (!euSize) { // EU does not exist
finish(this.errorMask | 0x20, 0); // set D27F for EU not ready
this.errorMask = 0;
} else {
if (segAddr < 0 || segAddr >= euSize) { // if read is past end of disk
this.errorMask |= 0x20; // set D27F for invalid seg address
}
this.timer = setTimeout(function writeInterrogateTimeout() {
finish(that.errorMask, length);
that.errorMask = 0;
}, Math.random()*this.maxLatency*1000 + this.initiateStamp - new Date().getTime());
}
};
/**************************************/
B5500DiskUnit.prototype.shutDown = function shutDown() {
/* Shuts down the device */
if (this.timer) {
clearTimeout(this.timer);
}
// this device has no window to close
};