diff --git a/conf/conf.go b/conf/conf.go
index 75ca0db..ffd8baf 100644
--- a/conf/conf.go
+++ b/conf/conf.go
@@ -8,12 +8,14 @@ import (
 	"github.com/udhos/jazigo/store"
 )
 
+// Change stores info about last config change.
 type Change struct {
 	When time.Time
 	By   string
 	From string
 }
 
+// AppConfig is persistent global configuration.
 type AppConfig struct {
 	MaxConfigFiles    int
 	Holdtime          time.Duration
@@ -24,6 +26,7 @@ type AppConfig struct {
 	Comment           string // free user-defined field
 }
 
+// NewAppConfigFromString creates AppConfig from string.
 func NewAppConfigFromString(str string) (*AppConfig, error) {
 	b := []byte(str)
 	c := &AppConfig{}
@@ -33,6 +36,7 @@ func NewAppConfigFromString(str string) (*AppConfig, error) {
 	return c, nil
 }
 
+// Dump exports AppConfig as YAML.
 func (a *AppConfig) Dump() ([]byte, error) {
 	b, err := yaml.Marshal(a)
 	if err != nil {
@@ -41,6 +45,7 @@ func (a *AppConfig) Dump() ([]byte, error) {
 	return b, nil
 }
 
+// NewDevAttr creates a new set of DevAttributes.
 func NewDevAttr() DevAttributes {
 	a := DevAttributes{
 		ErrlogHistSize: 60, // default max number of lines in errlog history
@@ -49,6 +54,7 @@ func NewDevAttr() DevAttributes {
 	return a
 }
 
+// DevAttributes is per-model set of default attributes for device.
 type DevAttributes struct {
 	NeedLoginChat                bool          // need login chat
 	NeedEnabledMode              bool          // need enabled mode
@@ -83,6 +89,7 @@ type DevAttributes struct {
 	CommandMatchTimeout time.Duration // larger timeout for slow responses (slow show running)
 }
 
+// DevConfig is full set of device properties.
 type DevConfig struct {
 	Debug          bool
 	Deleted        bool
@@ -98,6 +105,7 @@ type DevConfig struct {
 	Attr           DevAttributes
 }
 
+// NewDeviceFromString creates device configuration from string.
 func NewDeviceFromString(str string) (*DevConfig, error) {
 	b := []byte(str)
 	c := &DevConfig{}
@@ -107,6 +115,7 @@ func NewDeviceFromString(str string) (*DevConfig, error) {
 	return c, nil
 }
 
+// Dump exports device properties as YAML.
 func (c *DevConfig) Dump() ([]byte, error) {
 	b, err := yaml.Marshal(c)
 	if err != nil {
@@ -115,11 +124,13 @@ func (c *DevConfig) Dump() ([]byte, error) {
 	return b, nil
 }
 
+// Config is full (global+devices) app configuration.
 type Config struct {
 	Options AppConfig
 	Devices []DevConfig
 }
 
+// New creates new full app configuration.
 func New() *Config {
 	return &Config{
 		Options: AppConfig{
@@ -133,6 +144,7 @@ func New() *Config {
 	}
 }
 
+// Load loads a Config from file.
 func Load(path string, maxSize int64) (*Config, error) {
 	b, readErr := store.FileRead(path, maxSize)
 	if readErr != nil {
@@ -145,6 +157,7 @@ func Load(path string, maxSize int64) (*Config, error) {
 	return c, nil
 }
 
+// Dump exports device properties as YAML.
 func (c *Config) Dump() ([]byte, error) {
 	b, err := yaml.Marshal(c)
 	if err != nil {
diff --git a/conf/options.go b/conf/options.go
index ed71103..eb6599b 100644
--- a/conf/options.go
+++ b/conf/options.go
@@ -4,15 +4,18 @@ import (
 	"sync"
 )
 
+// Options provides concurrency-safe access to AppConfig.
 type Options struct {
 	options AppConfig
 	lock    sync.RWMutex
 }
 
+// NewOptions creates a new set of options.
 func NewOptions() *Options {
 	return &Options{}
 }
 
+// Get creates a copy of AppConfig.
 func (o *Options) Get() *AppConfig {
 	o.lock.RLock()
 	defer o.lock.RUnlock()
@@ -20,6 +23,7 @@ func (o *Options) Get() *AppConfig {
 	return &opt
 }
 
+// Set updates the AppConfig from a copy.
 func (o *Options) Set(c *AppConfig) {
 	o.lock.Lock()
 	defer o.lock.Unlock()
diff --git a/dev/errlog.go b/dev/errlog.go
index 4ae3271..9a8cc45 100644
--- a/dev/errlog.go
+++ b/dev/errlog.go
@@ -9,6 +9,7 @@ import (
 	"time"
 )
 
+// ErrlogPath builds the full pathname for errlog file.
 func ErrlogPath(pathPrefix, id string) string {
 	dir := filepath.Dir(pathPrefix)
 	path := filepath.Join(dir, id) + ".errlog"
@@ -19,7 +20,7 @@ func errlog(logger hasPrintf, result FetchResult, pathPrefix string, debug bool,
 
 	now := time.Now()
 
-	path := ErrlogPath(pathPrefix, result.DevId)
+	path := ErrlogPath(pathPrefix, result.DevID)
 
 	f, openErr := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0640)
 	if openErr != nil {
@@ -58,7 +59,7 @@ func errlog(logger hasPrintf, result FetchResult, pathPrefix string, debug bool,
 		now.String(),
 		result.Code == fetchErrNone,
 		result.End.Sub(result.Begin),
-		result.Model, result.DevId, result.DevHostPort, result.Transport, result.Code, result.Msg)
+		result.Model, result.DevID, result.DevHostPort, result.Transport, result.Code, result.Msg)
 
 	if debug {
 		logger.Printf("errlog debug: push: '%s': [%s]", path, msg)
diff --git a/dev/filter.go b/dev/filter.go
index 4ec65ff..f2b7eff 100644
--- a/dev/filter.go
+++ b/dev/filter.go
@@ -5,6 +5,7 @@ import (
 	"strconv"
 )
 
+// FilterTable stores line filters for custom line-by-line processing of configuration.
 type FilterTable struct {
 	table map[string]FilterFunc
 	re1   *regexp.Regexp
@@ -13,8 +14,10 @@ type FilterTable struct {
 	re4   *regexp.Regexp
 }
 
+// FilterFunc is a helper function type for line filters.
 type FilterFunc func(hasPrintf, bool, *FilterTable, []byte, int) []byte
 
+// NewFilterTable creates a filter table.
 func NewFilterTable(logger hasPrintf) *FilterTable {
 	t := &FilterTable{
 		table: map[string]FilterFunc{},
diff --git a/dev/model.go b/dev/model.go
index 1e4db82..8332a7c 100644
--- a/dev/model.go
+++ b/dev/model.go
@@ -12,11 +12,13 @@ import (
 	"github.com/udhos/jazigo/store"
 )
 
+// Model provides default attributes for model of devices.
 type Model struct {
 	name        string
 	defaultAttr conf.DevAttributes
 }
 
+// Device is an specific device.
 type Device struct {
 	conf.DevConfig
 
@@ -28,6 +30,7 @@ type Device struct {
 	lastElapsed time.Duration
 }
 
+// Username gets the username for login into a device.
 func (d *Device) Username() string {
 	if d.Model() == "mikrotik" {
 		return d.DevConfig.LoginUser + "+cte"
@@ -35,35 +38,43 @@ func (d *Device) Username() string {
 	return d.DevConfig.LoginUser
 }
 
+// Printf formats device-specific messages into logs.
 func (d *Device) Printf(format string, v ...interface{}) {
 	prefix := fmt.Sprintf("%s %s %s: ", d.DevConfig.Model, d.Id, d.HostPort)
 	d.logger.Printf(prefix+format, v...)
 }
 
+// Model gets the model name.
 func (d *Device) Model() string {
 	return d.devModel.name
 }
 
+// LastStatus gets a status string for last configuration backup.
 func (d *Device) LastStatus() bool {
 	return d.lastStatus
 }
 
+// LastTry provides the timestamp for the last backup attempt.
 func (d *Device) LastTry() time.Time {
 	return d.lastTry
 }
 
+// LastSuccess informs the timestamp for the last successful backup.
 func (d *Device) LastSuccess() time.Time {
 	return d.lastSuccess
 }
 
+// LastElapsed gets the elapsed time for the last backup attempt.
 func (d *Device) LastElapsed() time.Duration {
 	return d.lastElapsed
 }
 
+// Holdtime informs the devices' remaining holdtime.
 func (d *Device) Holdtime(now time.Time, holdtime time.Duration) time.Duration {
 	return holdtime - now.Sub(d.lastSuccess)
 }
 
+// RegisterModels adds known device models.
 func RegisterModels(logger hasPrintf, t *DeviceTable) {
 	registerModelFortiOS(logger, t)
 	registerModelCiscoAPIC(logger, t)
@@ -76,6 +87,7 @@ func RegisterModels(logger hasPrintf, t *DeviceTable) {
 	registerModelMikrotik(logger, t)
 }
 
+// CreateDevice creates a new device in the device table.
 func CreateDevice(tab *DeviceTable, logger hasPrintf, modelName, id, hostPort, transports, user, pass, enable string, debug bool, change *conf.Change) error {
 	logger.Printf("CreateDevice: %s %s %s %s", modelName, id, hostPort, transports)
 
@@ -101,6 +113,7 @@ func CreateDevice(tab *DeviceTable, logger hasPrintf, modelName, id, hostPort, t
 	return nil
 }
 
+// NewDeviceFromConf creates a new device from a DevConfig.
 func NewDeviceFromConf(tab *DeviceTable, logger hasPrintf, cfg *conf.DevConfig) (*Device, error) {
 	mod, getErr := tab.GetModel(cfg.Model)
 	if getErr != nil {
@@ -110,6 +123,7 @@ func NewDeviceFromConf(tab *DeviceTable, logger hasPrintf, cfg *conf.DevConfig)
 	return d, nil
 }
 
+// NewDevice creates a new device.
 func NewDevice(logger hasPrintf, mod *Model, id, hostPort, transports, loginUser, loginPassword, enablePassword string, debug bool) *Device {
 	d := &Device{logger: logger, devModel: mod, DevConfig: conf.DevConfig{Model: mod.name, Id: id, HostPort: hostPort, Transports: transports, LoginUser: loginUser, LoginPassword: loginPassword, EnablePassword: enablePassword, Debug: debug}}
 	d.Attr = mod.defaultAttr
@@ -127,14 +141,16 @@ const (
 	fetchErrSave     = 7
 )
 
+// FetchRequest is a request for fetching a device configuration.
 type FetchRequest struct {
 	Id        string           // fetch this device
 	ReplyChan chan FetchResult // reply on this channel
 }
 
+// FetchResult reports the result for fetching a device configuration.
 type FetchResult struct {
 	Model       string
-	DevId       string
+	DevID       string
 	DevHostPort string
 	Transport   string
 	Msg         string    // result error message
@@ -151,7 +167,8 @@ type dialog struct {
 	save [][]byte
 }
 
-// fetch runs in a per-device goroutine
+// Fetch captures a configuration for a device.
+// Fetch runs in a per-device goroutine.
 func (d *Device) Fetch(tab DeviceUpdater, logger hasPrintf, resultCh chan FetchResult, delay time.Duration, repository, logPathPrefix string, opt *conf.AppConfig, ft *FilterTable) {
 
 	result := d.fetch(logger, delay, repository, opt.MaxConfigFiles, ft)
@@ -191,7 +208,7 @@ func (d *Device) fetch(logger hasPrintf, delay time.Duration, repository string,
 
 	session, transport, logged, err := d.createTransport(logger)
 	if err != nil {
-		return FetchResult{Model: modelName, DevId: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("fetch transport: %v", err), Code: fetchErrTransp, Begin: begin}
+		return FetchResult{Model: modelName, DevID: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("fetch transport: %v", err), Code: fetchErrTransp, Begin: begin}
 	}
 
 	defer session.Close()
@@ -207,7 +224,7 @@ func (d *Device) fetch(logger hasPrintf, delay time.Duration, repository string,
 	if d.Attr.NeedLoginChat && !logged {
 		e, loginErr := d.login(logger, session, &capture)
 		if loginErr != nil {
-			return FetchResult{Model: modelName, DevId: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("fetch login: %v", loginErr), Code: fetchErrLogin, Begin: begin}
+			return FetchResult{Model: modelName, DevID: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("fetch login: %v", loginErr), Code: fetchErrLogin, Begin: begin}
 		}
 		if e {
 			enabled = true
@@ -219,7 +236,7 @@ func (d *Device) fetch(logger hasPrintf, delay time.Duration, repository string,
 	if d.Attr.NeedEnabledMode && !enabled {
 		enableErr := d.enable(logger, session, &capture)
 		if enableErr != nil {
-			return FetchResult{Model: modelName, DevId: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("fetch enable: %v", enableErr), Code: fetchErrEnable, Begin: begin}
+			return FetchResult{Model: modelName, DevID: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("fetch enable: %v", enableErr), Code: fetchErrEnable, Begin: begin}
 		}
 	}
 
@@ -228,7 +245,7 @@ func (d *Device) fetch(logger hasPrintf, delay time.Duration, repository string,
 	if d.Attr.NeedPagingOff {
 		pagingErr := d.pagingOff(logger, session, &capture)
 		if pagingErr != nil {
-			return FetchResult{Model: modelName, DevId: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("fetch pager off: %v", pagingErr), Code: fetchErrPager, Begin: begin}
+			return FetchResult{Model: modelName, DevID: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("fetch pager off: %v", pagingErr), Code: fetchErrPager, Begin: begin}
 		}
 	}
 
@@ -236,16 +253,16 @@ func (d *Device) fetch(logger hasPrintf, delay time.Duration, repository string,
 
 	if cmdErr := d.sendCommands(logger, session, &capture); cmdErr != nil {
 		d.saveRollback(logger, &capture)
-		return FetchResult{Model: modelName, DevId: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("commands: %v", cmdErr), Code: fetchErrCommands, Begin: begin}
+		return FetchResult{Model: modelName, DevID: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("commands: %v", cmdErr), Code: fetchErrCommands, Begin: begin}
 	}
 
 	d.debugf("will save results")
 
 	if saveErr := d.saveCommit(logger, &capture, repository, maxFiles, ft); saveErr != nil {
-		return FetchResult{Model: modelName, DevId: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("save commit: %v", saveErr), Code: fetchErrSave, Begin: begin}
+		return FetchResult{Model: modelName, DevID: d.Id, DevHostPort: d.HostPort, Transport: transport, Msg: fmt.Sprintf("save commit: %v", saveErr), Code: fetchErrSave, Begin: begin}
 	}
 
-	return FetchResult{Model: modelName, DevId: d.Id, DevHostPort: d.HostPort, Transport: transport, Code: fetchErrNone, Begin: begin}
+	return FetchResult{Model: modelName, DevID: d.Id, DevHostPort: d.HostPort, Transport: transport, Code: fetchErrNone, Begin: begin}
 }
 
 func (d *Device) saveRollback(logger hasPrintf, capture *dialog) {
@@ -256,18 +273,22 @@ func deviceDirectory(repository, id string) string {
 	return filepath.Join(repository, id)
 }
 
+// DeviceDir gets the directory used as device repository.
 func (d *Device) DeviceDir(repository string) string {
 	return deviceDirectory(repository, d.Id)
 }
 
+// DeviceFullPrefix gets the full path prefix for a device repository.
 func DeviceFullPrefix(repository, id string) string {
 	return filepath.Join(deviceDirectory(repository, id), id+".")
 }
 
+// DeviceFullPath get the full file path for a device repository.
 func DeviceFullPath(repository, id, file string) string {
 	return filepath.Join(repository, id, file)
 }
 
+// DevicePathPrefix gets the full path prefix for a device repository.
 func (d *Device) DevicePathPrefix(devDir string) string {
 	return filepath.Join(devDir, d.Id+".")
 }
@@ -449,10 +470,11 @@ READ_LOOP:
 	}
 }
 
+// Some constants.
 const (
-	BS = 'H' - '@'
-	CR = '\r'
-	LF = '\n'
+	BS = 'H' - '@' // BS backspace
+	CR = '\r'      // CR carriage return
+	LF = '\n'      // LF linefeed
 )
 
 func findLastLine(buf []byte) []byte {
@@ -745,7 +767,7 @@ func round(val float64) int {
 	return int(val + 0.5)
 }
 
-// ClearDeviceStatus: forget about last success (expire holdtime).
+// ClearDeviceStatus forgets about last success (expire holdtime).
 // Otherwise holdtime could prevent immediate backup.
 func ClearDeviceStatus(tab DeviceUpdater, devId string, logger hasPrintf, holdtime time.Duration) (*Device, error) {
 	d, getErr := tab.GetDevice(devId)
@@ -766,7 +788,7 @@ func ClearDeviceStatus(tab DeviceUpdater, devId string, logger hasPrintf, holdti
 	return d, nil
 }
 
-// UpdateLastSuccess: load device last success from filesystem.
+// UpdateLastSuccess loads device last success from filesystem.
 func UpdateLastSuccess(tab *DeviceTable, logger hasPrintf, repository string) {
 	for _, d := range tab.ListDevices() {
 		prefix := d.DevicePathPrefix(d.DeviceDir(repository))
diff --git a/dev/scan.go b/dev/scan.go
index 5400405..a26e440 100644
--- a/dev/scan.go
+++ b/dev/scan.go
@@ -7,7 +7,7 @@ import (
 	"github.com/udhos/jazigo/conf"
 )
 
-// Spawner: launches new goroutines to fetch requests received on channel reqChan
+// Spawner launches new goroutines to fetch requests received on channel reqChan.
 func Spawner(tab DeviceUpdater, logger hasPrintf, reqChan chan FetchRequest, repository, logPathPrefix string, options *conf.Options, ft *FilterTable) {
 
 	logger.Printf("Spawner: starting")
@@ -21,12 +21,12 @@ func Spawner(tab DeviceUpdater, logger hasPrintf, reqChan chan FetchRequest, rep
 
 		replyChan := req.ReplyChan // alias
 
-		devId := req.Id
-		d, getErr := tab.GetDevice(devId)
+		devID := req.Id
+		d, getErr := tab.GetDevice(devID)
 		if getErr != nil {
 			if replyChan != nil {
 				now := time.Now()
-				replyChan <- FetchResult{DevId: devId, Msg: fmt.Sprintf("Spawner: could not find device: %v", getErr), Code: fetchErrGetDev, Begin: now, End: now}
+				replyChan <- FetchResult{DevID: devID, Msg: fmt.Sprintf("Spawner: could not find device: %v", getErr), Code: fetchErrGetDev, Begin: now, End: now}
 			}
 			continue
 		}
@@ -38,7 +38,7 @@ func Spawner(tab DeviceUpdater, logger hasPrintf, reqChan chan FetchRequest, rep
 	logger.Printf("Spawner: exiting")
 }
 
-// Scan: new scheduler
+// Scan scans the list of devices dispatching backup requests to the Spawner thru the request channel reqChan.
 func Scan(tab DeviceUpdater, devices []*Device, logger hasPrintf, opt *conf.AppConfig, reqChan chan FetchRequest) (int, int, int) {
 
 	deviceCount := len(devices)
@@ -97,7 +97,7 @@ func Scan(tab DeviceUpdater, devices []*Device, logger hasPrintf, opt *conf.AppC
 
 		end := time.Now()
 		elap := end.Sub(r.Begin)
-		logger.Printf("Scan: recv %s %s %s %s msg=[%s] code=%d wait=%d remain=%d skipped=%d elap=%s", r.Model, r.DevId, r.DevHostPort, r.Transport, r.Msg, r.Code, wait, deviceCount-nextDevice, skipped, elap)
+		logger.Printf("Scan: recv %s %s %s %s msg=[%s] code=%d wait=%d remain=%d skipped=%d elap=%s", r.Model, r.DevID, r.DevHostPort, r.Transport, r.Msg, r.Code, wait, deviceCount-nextDevice, skipped, elap)
 
 		good := r.Code == fetchErrNone
 
@@ -120,10 +120,10 @@ func Scan(tab DeviceUpdater, devices []*Device, logger hasPrintf, opt *conf.AppC
 	return success, deviceCount - success, skipped + deleted
 }
 
-func updateDeviceStatus(tab DeviceUpdater, devId string, good bool, last time.Time, elapsed time.Duration, logger hasPrintf, holdtime time.Duration) {
-	d, getErr := tab.GetDevice(devId)
+func updateDeviceStatus(tab DeviceUpdater, devID string, good bool, last time.Time, elapsed time.Duration, logger hasPrintf, holdtime time.Duration) {
+	d, getErr := tab.GetDevice(devID)
 	if getErr != nil {
-		logger.Printf("updateDeviceStatus: '%s' not found: %v", devId, getErr)
+		logger.Printf("updateDeviceStatus: '%s' not found: %v", devID, getErr)
 		return
 	}
 
@@ -140,5 +140,5 @@ func updateDeviceStatus(tab DeviceUpdater, devId string, good bool, last time.Ti
 	tab.UpdateDevice(d)
 
 	h2 := d.Holdtime(now, holdtime)
-	logger.Printf("updateDeviceStatus: device %s holdtime: old=%v new=%v", devId, h1, h2)
+	logger.Printf("updateDeviceStatus: device %s holdtime: old=%v new=%v", devID, h1, h2)
 }
diff --git a/dev/table.go b/dev/table.go
index fa56b7a..36f2c2b 100644
--- a/dev/table.go
+++ b/dev/table.go
@@ -7,7 +7,7 @@ import (
 	"sync"
 )
 
-// DeviceTable: goroutine concurrency-safe DeviceTable.
+// DeviceTable is goroutine concurrency-safe list of devices.
 // Data is fully copied when either entering or leaving DeviceTable.
 // Data is not shared with pointers.
 type DeviceTable struct {
@@ -16,15 +16,18 @@ type DeviceTable struct {
 	lock    sync.RWMutex
 }
 
+// DeviceUpdater is helper interface for a device store which can provide and update device information.
 type DeviceUpdater interface {
 	GetDevice(id string) (*Device, error)
 	UpdateDevice(d *Device) error
 }
 
+// NewDeviceTable creates a device table.
 func NewDeviceTable() *DeviceTable {
 	return &DeviceTable{models: map[string]*Model{}, devices: map[string]*Device{}, lock: sync.RWMutex{}}
 }
 
+// GetModel looks up a model in the device table.
 func (t *DeviceTable) GetModel(modelName string) (*Model, error) {
 	t.lock.RLock()
 	defer t.lock.RUnlock()
@@ -37,6 +40,7 @@ func (t *DeviceTable) GetModel(modelName string) (*Model, error) {
 	return nil, fmt.Errorf("DeviceTable.GetModel: not found")
 }
 
+// SetModel adds a model to the device table.
 func (t *DeviceTable) SetModel(m *Model, logger hasPrintf) error {
 
 	logger.Printf("DeviceTable.SetModel: registering model: '%s'", m.name)
@@ -53,6 +57,7 @@ func (t *DeviceTable) SetModel(m *Model, logger hasPrintf) error {
 	return nil
 }
 
+// GetDevice finds a device in the device table.
 func (t *DeviceTable) GetDevice(id string) (*Device, error) {
 	t.lock.RLock()
 	defer t.lock.RUnlock()
@@ -65,6 +70,7 @@ func (t *DeviceTable) GetDevice(id string) (*Device, error) {
 	return nil, fmt.Errorf("DeviceTable.GetDevice: not found")
 }
 
+// SetDevice adds a device into the device table.
 func (t *DeviceTable) SetDevice(d *Device) error {
 	t.lock.Lock()
 	defer t.lock.Unlock()
@@ -79,6 +85,7 @@ func (t *DeviceTable) SetDevice(d *Device) error {
 	return nil
 }
 
+// DeleteDevice sets a device as deleted in the device table.
 func (t *DeviceTable) DeleteDevice(id string) {
 	t.lock.Lock()
 	defer t.lock.Unlock()
@@ -88,6 +95,7 @@ func (t *DeviceTable) DeleteDevice(id string) {
 	}
 }
 
+// PurgeDevice actually removes a device from the device table.
 func (t *DeviceTable) PurgeDevice(id string) {
 	t.lock.Lock()
 	defer t.lock.Unlock()
@@ -95,6 +103,7 @@ func (t *DeviceTable) PurgeDevice(id string) {
 	delete(t.devices, id)
 }
 
+// UpdateDevice updates device info in the device table.
 func (t *DeviceTable) UpdateDevice(d *Device) error {
 	t.lock.Lock()
 	defer t.lock.Unlock()
@@ -109,6 +118,7 @@ func (t *DeviceTable) UpdateDevice(d *Device) error {
 	return nil
 }
 
+// ListDevices gets the list of devices.
 func (t *DeviceTable) ListDevices() []*Device {
 	t.lock.RLock()
 	defer t.lock.RUnlock()
@@ -127,7 +137,8 @@ func copyDeviceMapToSlice(m map[string]*Device) []*Device {
 	return devices
 }
 
-func (t *DeviceTable) FindDeviceFreeId(prefix string) string {
+// FindDeviceFreeID finds an ID available for a new device.
+func (t *DeviceTable) FindDeviceFreeID(prefix string) string {
 	pLen := len(prefix)
 	devices := t.ListDevices()
 	highest := 0
@@ -149,6 +160,7 @@ func (t *DeviceTable) FindDeviceFreeId(prefix string) string {
 	return prefix + strconv.Itoa(free)
 }
 
+// ListModels gets the list of models.
 func (t *DeviceTable) ListModels() []string {
 	t.lock.RLock()
 	defer t.lock.RUnlock()
diff --git a/dev/transport.go b/dev/transport.go
index 827c16e..80bcbd7 100644
--- a/dev/transport.go
+++ b/dev/transport.go
@@ -151,14 +151,14 @@ func (s *transpSSH) Close() error {
 	return nil
 }
 
-func openTransportPipe(logger hasPrintf, modelName, devId, hostPort, transports, user, pass string, args []string, debug bool, timeout time.Duration) (transp, string, bool, error) {
-	s, err := openPipe(logger, modelName, devId, hostPort, transports, user, pass, args, debug, timeout)
+func openTransportPipe(logger hasPrintf, modelName, devID, hostPort, transports, user, pass string, args []string, debug bool, timeout time.Duration) (transp, string, bool, error) {
+	s, err := openPipe(logger, modelName, devID, hostPort, transports, user, pass, args, debug, timeout)
 	return s, "pipe", true, err
 }
 
-func openPipe(logger hasPrintf, modelName, devId, hostPort, transports, user, pass string, args []string, debug bool, timeout time.Duration) (transp, error) {
+func openPipe(logger hasPrintf, modelName, devID, hostPort, transports, user, pass string, args []string, debug bool, timeout time.Duration) (transp, error) {
 
-	devLabel := fmt.Sprintf("%s %s %s", modelName, devId, hostPort)
+	devLabel := fmt.Sprintf("%s %s %s", modelName, devID, hostPort)
 
 	logger.Printf("openPipe: %s - opening", devLabel)
 
@@ -194,7 +194,7 @@ func openPipe(logger hasPrintf, modelName, devId, hostPort, transports, user, pa
 
 	logger.Printf("openPipe: %s - starting", devLabel)
 
-	os.Setenv("JAZIGO_DEV_ID", devId)
+	os.Setenv("JAZIGO_DEV_ID", devID)
 	os.Setenv("JAZIGO_DEV_HOSTPORT", hostPort)
 	os.Setenv("JAZIGO_DEV_USER", user)
 	os.Setenv("JAZIGO_DEV_PASS", pass)
@@ -209,7 +209,7 @@ func openPipe(logger hasPrintf, modelName, devId, hostPort, transports, user, pa
 	return s, nil
 }
 
-func openTransport(logger hasPrintf, modelName, devId, hostPort, transports, user, pass string) (transp, string, bool, error) {
+func openTransport(logger hasPrintf, modelName, devID, hostPort, transports, user, pass string) (transp, string, bool, error) {
 	tList := strings.Split(transports, ",")
 	if len(tList) < 1 {
 		return nil, transports, false, fmt.Errorf("openTransport: missing transports: [%s]", transports)
@@ -223,7 +223,7 @@ func openTransport(logger hasPrintf, modelName, devId, hostPort, transports, use
 		switch t {
 		case "ssh":
 			hp := forceHostPort(hostPort, "22")
-			s, err := openSSH(logger, modelName, devId, hp, timeout, user, pass)
+			s, err := openSSH(logger, modelName, devID, hp, timeout, user, pass)
 			if err == nil {
 				return s, t, true, nil
 			}
@@ -231,14 +231,14 @@ func openTransport(logger hasPrintf, modelName, devId, hostPort, transports, use
 			lastErr = err
 		case "telnet":
 			hp := forceHostPort(hostPort, "23")
-			s, err := openTelnet(logger, modelName, devId, hp, timeout)
+			s, err := openTelnet(logger, modelName, devID, hp, timeout)
 			if err == nil {
 				return s, t, false, nil
 			}
 			logger.Printf("openTransport: %v", err)
 			lastErr = err
 		default:
-			s, err := openTCP(logger, modelName, devId, hostPort, timeout)
+			s, err := openTCP(logger, modelName, devID, hostPort, timeout)
 			if err == nil {
 				return s, t, false, nil
 			}
@@ -247,7 +247,7 @@ func openTransport(logger hasPrintf, modelName, devId, hostPort, transports, use
 		}
 	}
 
-	return nil, transports, false, fmt.Errorf("openTransport: %s %s %s %s - unable to open transport: last error: %v", modelName, devId, hostPort, transports, lastErr)
+	return nil, transports, false, fmt.Errorf("openTransport: %s %s %s %s - unable to open transport: last error: %v", modelName, devID, hostPort, transports, lastErr)
 }
 
 func forceHostPort(hostPort, defaultPort string) string {
@@ -258,11 +258,11 @@ func forceHostPort(hostPort, defaultPort string) string {
 	return hostPort
 }
 
-func openSSH(logger hasPrintf, modelName, devId, hostPort string, timeout time.Duration, user, pass string) (transp, error) {
+func openSSH(logger hasPrintf, modelName, devID, hostPort string, timeout time.Duration, user, pass string) (transp, error) {
 
 	conn, dialErr := net.DialTimeout("tcp", hostPort, timeout)
 	if dialErr != nil {
-		return nil, fmt.Errorf("openSSH: Dial: %s %s %s - %v", modelName, devId, hostPort, dialErr)
+		return nil, fmt.Errorf("openSSH: Dial: %s %s %s - %v", modelName, devID, hostPort, dialErr)
 	}
 
 	conf := &ssh.Config{}
@@ -280,12 +280,12 @@ func openSSH(logger hasPrintf, modelName, devId, hostPort string, timeout time.D
 
 	c, chans, reqs, connErr := ssh.NewClientConn(conn, hostPort, config)
 	if connErr != nil {
-		return nil, fmt.Errorf("openSSH: NewClientConn: %s %s %s - %v", modelName, devId, hostPort, connErr)
+		return nil, fmt.Errorf("openSSH: NewClientConn: %s %s %s - %v", modelName, devID, hostPort, connErr)
 	}
 
 	cli := ssh.NewClient(c, chans, reqs)
 
-	s := &transpSSH{conn: conn, client: cli, devLabel: fmt.Sprintf("%s %s %s", modelName, devId, hostPort) /*, logger: logger*/}
+	s := &transpSSH{conn: conn, client: cli, devLabel: fmt.Sprintf("%s %s %s", modelName, devID, hostPort) /*, logger: logger*/}
 
 	ses, sessionErr := s.client.NewSession()
 	if sessionErr != nil {
@@ -328,21 +328,21 @@ func openSSH(logger hasPrintf, modelName, devId, hostPort string, timeout time.D
 	return s, nil
 }
 
-func openTelnet(logger hasPrintf, modelName, devId, hostPort string, timeout time.Duration) (transp, error) {
+func openTelnet(logger hasPrintf, modelName, devID, hostPort string, timeout time.Duration) (transp, error) {
 
 	conn, err := net.DialTimeout("tcp", hostPort, timeout)
 	if err != nil {
-		return nil, fmt.Errorf("openTelnet: %s %s %s - %v", modelName, devId, hostPort, err)
+		return nil, fmt.Errorf("openTelnet: %s %s %s - %v", modelName, devID, hostPort, err)
 	}
 
 	return &transpTelnet{conn, logger}, nil
 }
 
-func openTCP(logger hasPrintf, modelName, devId, hostPort string, timeout time.Duration) (transp, error) {
+func openTCP(logger hasPrintf, modelName, devID, hostPort string, timeout time.Duration) (transp, error) {
 
 	conn, err := net.DialTimeout("tcp", hostPort, timeout)
 	if err != nil {
-		return nil, fmt.Errorf("openTCP: %s %s %s - %v", modelName, devId, hostPort, err)
+		return nil, fmt.Errorf("openTCP: %s %s %s - %v", modelName, devID, hostPort, err)
 	}
 
 	return &transpTCP{conn}, nil
diff --git a/jazigo/logg.go b/jazigo/logg.go
index 262eaca..63f8bb1 100644
--- a/jazigo/logg.go
+++ b/jazigo/logg.go
@@ -9,7 +9,8 @@ import (
 	"github.com/udhos/jazigo/store"
 )
 
-type logfile struct {
+// Logfile log stream implements io.Writer in order to be attachable to log.New()
+type Logfile struct {
 	logPathPrefix     string
 	maxFiles          int
 	maxFileSize       int64
@@ -20,8 +21,8 @@ type logfile struct {
 }
 
 // NewLogfile creates a new log stream capable of automatically saving to filesystem.
-func NewLogfile(prefix string, maxFiles int, maxSize int64, checkInterval time.Duration) *logfile {
-	l := &logfile{
+func NewLogfile(prefix string, maxFiles int, maxSize int64, checkInterval time.Duration) *Logfile {
+	l := &Logfile{
 		logPathPrefix:     prefix,
 		maxFiles:          maxFiles,
 		maxFileSize:       maxSize,
@@ -56,7 +57,7 @@ func touchFunc(w store.HasWrite) error {
 	return wrErr
 }
 
-func (l *logfile) rotate() {
+func (l *Logfile) rotate() {
 	if l.output != nil {
 		l.output.Close()
 		l.output = nil
@@ -68,19 +69,19 @@ func (l *logfile) rotate() {
 			l.output.Close()
 			l.output = nil
 		}
-		l.logger.Printf("logfile.rotate: could not find log path: %v", newErr)
+		l.logger.Printf("Logfile.rotate: could not find log path: %v", newErr)
 		return
 	}
 
 	var openErr error
 	l.output, openErr = openAppend(outputPath)
 	if openErr != nil {
-		l.logger.Printf("logfile.rotate: could not open log: %v", openErr)
+		l.logger.Printf("Logfile.rotate: could not open log: %v", openErr)
 	}
 }
 
 // Write implements io.Writer in order to be attached to log.New().
-func (l *logfile) Write(b []byte) (int, error) {
+func (l *Logfile) Write(b []byte) (int, error) {
 
 	if l.output == nil {
 		l.rotate()
diff --git a/jazigo/main.go b/jazigo/main.go
index 0b0c35b..75a1e2f 100644
--- a/jazigo/main.go
+++ b/jazigo/main.go
@@ -380,7 +380,7 @@ func manageDeviceList(jaz *app, imp, del, purge, list bool) error {
 		jaz.logf("reading device list from stdin")
 
 		autoID := "auto"
-		nextID := jaz.table.FindDeviceFreeId(autoID)
+		nextID := jaz.table.FindDeviceFreeID(autoID)
 		valueStr := nextID[len(autoID):]
 		value, valErr := strconv.Atoi(valueStr)
 		if valErr != nil {
diff --git a/jazigo/web_ui.go b/jazigo/web_ui.go
index 73a6fd0..a1786c6 100644
--- a/jazigo/web_ui.go
+++ b/jazigo/web_ui.go
@@ -790,7 +790,7 @@ func buildCreateDevPanel(jaz *app, s gwu.Session, refresh func(gwu.Event), creat
 
 	createAutoId := func() {
 		if strings.HasPrefix(textId.Text(), autoIdPrefix) {
-			textId.SetText(jaz.table.FindDeviceFreeId(autoIdPrefix))
+			textId.SetText(jaz.table.FindDeviceFreeID(autoIdPrefix))
 		}
 	}
 
@@ -803,7 +803,7 @@ func buildCreateDevPanel(jaz *app, s gwu.Session, refresh func(gwu.Event), creat
 		id := textId.Text()
 
 		if id == autoIdPrefix {
-			id = jaz.table.FindDeviceFreeId(autoIdPrefix)
+			id = jaz.table.FindDeviceFreeID(autoIdPrefix)
 		}
 
 		change := conf.Change{
diff --git a/store/s3.go b/store/s3.go
index 0120da9..efeeb88 100644
--- a/store/s3.go
+++ b/store/s3.go
@@ -415,6 +415,8 @@ func s3fileCompare(p1, p2 string, maxSize int64) (bool, error) {
 	return cmp.CompareReader(r1, r2)
 }
 
+// S3URL builds the URL for an S3 bucket.
+// The path is an ARN: "arn:aws:s3:region::bucket/folder/file.xxx"
 func S3URL(path string) string {
 	region, bucket, key := s3parse(path)
 
diff --git a/store/store.go b/store/store.go
index e106b1c..7f855bd 100644
--- a/store/store.go
+++ b/store/store.go
@@ -21,31 +21,32 @@ type hasPrintf interface {
 	Printf(fmt string, v ...interface{})
 }
 
-type sortByCommitId struct {
+type sortByCommitID struct {
 	data   []string
 	logger hasPrintf
 }
 
-func (s sortByCommitId) Len() int {
+func (s sortByCommitID) Len() int {
 	return len(s.data)
 }
-func (s sortByCommitId) Swap(i, j int) {
+func (s sortByCommitID) Swap(i, j int) {
 	s.data[i], s.data[j] = s.data[j], s.data[i]
 }
-func (s sortByCommitId) Less(i, j int) bool {
+func (s sortByCommitID) Less(i, j int) bool {
 	s1 := s.data[i]
-	id1, err1 := ExtractCommitIdFromFilename(s1)
+	id1, err1 := ExtractCommitIDFromFilename(s1)
 	if err1 != nil {
-		s.logger.Printf("sortByCommitId.Less: error parsing config file path: '%s': %v", s1, err1)
+		s.logger.Printf("sortByCommitID.Less: error parsing config file path: '%s': %v", s1, err1)
 	}
 	s2 := s.data[j]
-	id2, err2 := ExtractCommitIdFromFilename(s2)
+	id2, err2 := ExtractCommitIDFromFilename(s2)
 	if err2 != nil {
-		s.logger.Printf("sortByCommitId.Less: error parsing config file path: '%s': %v", s2, err2)
+		s.logger.Printf("sortByCommitID.Less: error parsing config file path: '%s': %v", s2, err2)
 	}
 	return id1 < id2
 }
 
+// Init starts the store by providing a logger and default S3 region.
 func Init(logger hasPrintf, region string) {
 	if logger == nil {
 		panic("store.Init: nil logger")
@@ -53,7 +54,8 @@ func Init(logger hasPrintf, region string) {
 	s3init(logger, region)
 }
 
-func ExtractCommitIdFromFilename(filename string) (int, error) {
+// ExtractCommitIDFromFilename gets the commit from a filename: "aaa.1" => 1
+func ExtractCommitIDFromFilename(filename string) (int, error) {
 	lastDot := strings.LastIndexByte(filename, '.')
 	commitId := filename[lastDot+1:]
 	id, err := strconv.Atoi(commitId)
@@ -99,6 +101,7 @@ func tryShortcut(configPathPrefix string, logger hasPrintf) string {
 	return "" // not found
 }
 
+// FindLastConfig finds the last file under a path prefix.
 func FindLastConfig(configPathPrefix string, logger hasPrintf) (string, error) {
 
 	if path := tryShortcut(configPathPrefix, logger); path != "" {
@@ -124,7 +127,7 @@ func FindLastConfig(configPathPrefix string, logger hasPrintf) (string, error) {
 	maxId := -1
 	last := ""
 	for _, m := range matches {
-		id, idErr := ExtractCommitIdFromFilename(m)
+		id, idErr := ExtractCommitIDFromFilename(m)
 		if idErr != nil {
 			return "", fmt.Errorf("FindLastConfig: bad commit id: %s: %v", m, idErr)
 		}
@@ -141,6 +144,7 @@ func FindLastConfig(configPathPrefix string, logger hasPrintf) (string, error) {
 	return lastPath, nil
 }
 
+// ListConfigSorted retrieves the sorted list of files under a path prefix.
 func ListConfigSorted(configPathPrefix string, reverse bool, logger hasPrintf) (string, []string, error) {
 
 	dirname, matches, err := ListConfig(configPathPrefix, logger)
@@ -149,9 +153,9 @@ func ListConfigSorted(configPathPrefix string, reverse bool, logger hasPrintf) (
 	}
 
 	if reverse {
-		sort.Sort(sort.Reverse(sortByCommitId{data: matches, logger: logger}))
+		sort.Sort(sort.Reverse(sortByCommitID{data: matches, logger: logger}))
 	} else {
-		sort.Sort(sortByCommitId{data: matches, logger: logger})
+		sort.Sort(sortByCommitID{data: matches, logger: logger})
 	}
 
 	return dirname, matches, nil
@@ -180,6 +184,7 @@ func dirList(path string) (string, []string, error) {
 	return dirname, names, nil
 }
 
+// ListConfig retrieves files under a path prefix.
 func ListConfig(configPathPrefix string, logger hasPrintf) (string, []string, error) {
 
 	var dirname string
@@ -206,6 +211,7 @@ func ListConfig(configPathPrefix string, logger hasPrintf) (string, []string, er
 	return dirname, matches, nil
 }
 
+// HasWrite is a helper interface for types providing the method Write().
 type HasWrite interface {
 	Write(p []byte) (int, error)
 }
@@ -249,6 +255,7 @@ func fileRename(p1, p2 string) error {
 	return os.Rename(p1, p2)
 }
 
+// FileRead reads bytes from file.
 func FileRead(path string, maxSize int64) ([]byte, error) {
 
 	var r *io.LimitedReader
@@ -324,6 +331,7 @@ func writeFile(path string, writeFunc func(HasWrite) error, contentType string)
 	return nil
 }
 
+// SaveNewConfig saves data to a new file. The function writeFunc must be provided to issue the actual data.
 func SaveNewConfig(configPathPrefix string, maxFiles int, logger hasPrintf, writeFunc func(HasWrite) error, changesOnly bool, contentType string) (string, error) {
 
 	// get tmp file
@@ -351,7 +359,7 @@ func SaveNewConfig(configPathPrefix string, maxFiles int, logger hasPrintf, writ
 		previousFound = false
 	}
 
-	id, err2 := ExtractCommitIdFromFilename(lastConfig)
+	id, err2 := ExtractCommitIDFromFilename(lastConfig)
 	if err2 != nil {
 		logger.Printf("SaveNewConfig: error parsing config path: [%s]: %v", lastConfig, err2)
 	}
@@ -440,6 +448,7 @@ func eraseOldFiles(configPathPrefix string, maxFiles int, logger hasPrintf) {
 	}
 }
 
+// FileInfo returns file modification time and size.
 func FileInfo(path string) (time.Time, int64, error) {
 
 	if s3path(path) {
@@ -465,6 +474,7 @@ func fileCompare(p1, p2 string) (bool, error) {
 	return cmp.CompareFile(p1, p2)
 }
 
+// MkDir creates a new directory.
 func MkDir(path string) error {
 
 	if s3path(path) {